Probiotik, Solusi Untuk Bayi Kolik

Kolik cukup banyak dialami bayi baru lahir. Nah, gejala yang paling mudah dikenali adalah tangisannya yang membahana. Tak heran, kan, bila para Mama langsung panik. Apa yang sebenarnya terjadi, sih?

Menurut dr. IGAN Partiwi Surjadi, Sp.A, MARS, dari RS Bunda, Jakarta, “Kolik adalah gejala sakit perut pada bayi, yang ditandai dengan tangisan terus-menerus dan bayi tampak kesakitan."

Ya, bayi yang menderita kolik akan menangis tanpa henti, paling tidak selama 3 jam per hari, 3 hari seminggu, dan biasanya berlangsung selama 3 minggu. Tanda-tanda umum ini dikenal pula sebagai gejala kolik “serba 3”. Suatu penelitian menyebutkan, kolik dialami hampir sekitar 28% bayi baru lahir.

Dr. Miriam Stoppard, M.D, D.Sc, DCL, FRCP, OBE, dokter anak dan penulis berbagai buku kesehatan, menambahkan, bayi menderita kolik bila tangisannya disertai  wajah yang memerah dan kedua kakinya diangkat ke perut karena kesakitan. Apa lagi? Biasanya, ia menangis menjelang malam. Sayangnya nih, penyebabnya masih belum diketahui secara persis. Untungnya, gangguan ini akan menghilang setelah si kecil berusia empat bulan.

Berbagai teknik terkini untuk mengatasi kolik pun terus diteliti. Salah satu di antaranya adalah memanfaatkan probiotik. Bakteri yang menguntungkan ini memang berfungsi melancarkan sistem pencernaan dan memelihara fungsi sistem imuntas tubuh. Nah, perut kembung akibat gas dan sembelit diduga menjadi salah satu penyebab kolik pada bayi.

Makanya, para peneliti mulai mencari cara untuk menambahkan probiotik ke dalam susu formula dan makanan bayi. Berdasarkan sebuah penelitian yang dilakukan di Italia, dalam waktu seminggu setelah pemberian cairan yang mengandung Lactobacillus reuteri Protectis (salah satu tipe probiotik), tangisan bayi yang mengalami kolik bisa dikurangi hingga 74%.

Setelah tiga minggu, tangisan bayi yang tadinya berlangsung selama 370 menit setiap hari berkurang hingga 35 menit per hari. Juga, dalam pup si kecil terjadi pengurangan jumlah bakteri E. coli yang membahayakan.

Jadi, apa, sih, kelebihan probiotik? “Probiotik bisa mengurangi gas dan meningkatkan pola gerakan usus. Makanya, memberi asupan probiotik di usia dini dan memelihara keberadaannya di dalam tubuh adalah langkah penting dalam memelihara kesehatan bayi,” kata Leo A. Heitlinger, M.D., dokter anak bagian gastroenterologi dari Bethlehem, Pennsylvania.

Kabar baiknya adalah, dr. IGAN Partiwi Surjadi, Sp.A, MARS, dari RS Bunda, Jakarta, menyatakan, sumber probiotik yang terbaik bagi bayi itu tak lain adalah ASI alias Air Susu Ibu! Ayo, Ma, segera susui si kecil. (Indita Indriani/Foto: dok.Feminagroup)

Penanganan Terkini Transient Tachypnea of the Newborn (TTN)

Transient Tachypnea of the Newborn (TTN) atau sering juga disebut Transient Respiratory Distress of the Newborn (TRDN) adalah penyakit self-limited disease yang terjadi pada banyak bayi di seluruh dunia dan dihadapi oleh semua dokter yang merawat bayi baru lahir. Bayi baru lahir dengan TTN yang baru lahir dalam beberapa jam pertama kehidupan dengan takipnea, terjadi peningkatan kebutuhan oksigen, dan ABGs yang tidak mencerminkan retensi karbon dioksida. Ketika mengelola TTN yang baru lahir, mengamati tanda-tanda penurunan klinis yang mungkin dipikirkan diagnosis lain dalam gangguan repiratory sistress lainnya adalah sangat penting. Bayi baru lahir dengan TTN biasanya sering dianggap dan didiagnosis sebagai sebagai Congenital Pnemoni, Aspirasi Pnemoni atau gangguan Hyaline membrane disease (HMD). Pada HMD biasanya terjadi pada bayi dengan usia kehamilan di bawah 35 minggu. Sehingga bila bayi sesak di atas usia kehamilan 35 minggu yang paling sering dipikirkan adalan TTN.
Dari seluruh bayi yang lahir, sekitar 1% akan mengalami kesulitan bernapas, ditandai dengan napas cepat (frekuensi >60 kali permenit, diperiksa dengan stetoskop di jantung per 6 detik), sianosis perifer dan sentral, merintih, retraksi sternal, napas cuping hidup, hingga apneu periodik. Kumpulan gejala tersebut dikenal dengan istilah Sindrom Gawat Napas (SGN). SGN ini meliputi Respiratory Distress Syndrome (RDS) akibat paru yang belum matang, sindrom aspirasi mekonium, serta Transient Tachypnea of the Newborn (TTN) atau wet lung syndrome. Bayi dengan TTN selain takipneu, juga terjadi peningkatan kebutuhan oksigen dan analisis gas darah yang menunjukkan retensi karbondioksida. Dalam tatalaksana TTN, observasi tanda vital dan perburukan klinis sangat penting karena dapat menjadi diagnosis lain serta menimbulkan fatigue saluran pernapasan.
Patofisiologi

• Penyakit pernapasan menular akut berkembang pada sekitar 1% dari semua bayi yang baru lahir dan mengakibatkan perawatan NICU. Bayi baru lahir dengan TTN adalah hasil dari keterlambatan dalam clearance cairan paru janin. Dalam penderitaan, melewati pernapasan dianggap masalah defisiensi surfaktan relatif tetapi sekarang dicirikan oleh beban wilayah udara-cairan sekunder terhadap ketidakmampuan untuk menyerap cairan paru janin.
• Dalam percobaan In vivo telah menunjukkan bahwa epitel paru-paru mengeluarkan Cl-dan cairan selama kehamilan tetapi mengembangkan kemampuan untuk menyerap kembali aktif Na + hanya selama kehamilan terlambat. Saat lahir, switch paru matang dari aktif Cl-(cairan) sekresi untuk aktif penyerapan Na + (cairan) menanggapi beredar katekolamin;.
• Baru-baru ini, bukti menunjukkan glukokortikoid berperan dalam switch ini .
• Perubahan tekanan oksigen menambah Na +-mengangkut kapasitas epitel dan ekspresi peningkatan gen untuk Na + epitel saluran (ENaC). Ketidakmampuan paru janin belum matang untuk beralih dari sekresi cairan hasil penyerapan cairan, sebagian besar, dari ketidakdewasaan dalam ekspresi ENaC, yang dapat up-diatur oleh glukokortikoid. Glukokortikoid menginduksi paru Na + reabsorpsi kemungkinan besar melalui saluran ENaC paru pada akhir usia kehamilan janin alveolar epitel.
• Kedua blokade farmakologis saluran ENaC paru-paru dan percobaan KO genetik menggunakan tikus kekurangan dalam subunit pori pembentuk ENaC telah menunjukkan pentingnya fisiologis penting dari paru-paru + transport Na saat lahir. Ketika Na + transportasi tidak efektif, hewan yang baru lahir mengembangkan gangguan pernapasan; hipoksemia; paru retensi cairan janin, dan, dalam kasus tikus KO ENaC, kematian. Studi bioelectrical bayi manusia ‘hidung epitel menunjukkan bahwa kedua takipnea transien dari sindrom gangguan baru lahir dan pernafasan (RDS) melibatkan cacat amilorid sensitif Na transportasi +.
• Bayi dewasa memiliki transisi normal dari janin untuk hidup pascakelahiran memiliki surfaktan matang dan sistem epitel. Bayi baru lahir dengan TTN terjadi pada bayi baru lahir dewasa dengan jalur surfaktan matang dan kurang berkembang pernapasan epitel Na + transportasi, sedangkan RDS neonatal terjadi pada bayi dengan kedua jalur surfaktan dini dan Na + dewasa transportasi.
• Seorang bayi lahir dengan kelahiran sesar beresiko memiliki cairan paru yang berlebihan sebagai akibat dari tidak pernah dialami semua tahapan kerja dan kurangnya berikutnya lonjakan katekolamin yang tepat, yang menghasilkan rilis rendah kontra-regulasi hormon pada saat persalinan. Hasil akhirnya adalah alveoli dengan cairan dipertahankan yang menghambat pertukaran gas. Bayi yang dilahirkan dengan sectio caesarea mengalami risiko retensi cairan paru yang lebih besar dibanding partus spontan dengan seluruh tahapan persalinan karena kurang stimulasi katekolamin. Kurangnya stimulus menyebabkan kurangnya produksi steroid saat dilahirkan, sehingga alevoli akan ‘becek’ akibat kegagalan transpor cairan. Pertukaran gas pun terhambat.
• Mekanisme ENaC dan perubahan fungsi epitel berperan sangat penting dalam transpor Na+ epitel paru waktu lahir. Ketika transpor Na+ tidak efektif, percobaan pada tikus menunjukkan gagal napas, hipoksemia, retensi cairan paru fetus, hingga kematian. Penelitian pada manusia juga menunjukkan bahwa TTN dan RDS melibatkan transpor Na+ yang rusak. Bayi dengan paru yang matang akan mengalami transisi normal dari kehidupan fetus ke postnatal dengan surfaktan yang cukup dan sistem epitel yang sempurna. TTN terjadi pada bayi matur dengan surfaktan yang cukup namun transpor Na+ epitel yang terganggu. Sedangkan RDS terjadi pada bayi yang mengalami kerusakan epitel sekaligus kekurangan surfaktan.

Epidemiologi

• Sekitar 1% bayi memiliki beberapa bentuk gangguan pernapasan yang tidak berhubungan dengan infeksi. Gangguan pernapasan meliputi RDS (yaitu, penyakit membran hialin) dan takipnea transient yang baru lahir. Dari jumlah ini% 1, sekitar 33-50% memiliki takipnea transient yang baru lahir.
• Bayi baru lahir dengan TTN umumnya gangguannya terbatas tanpa morbiditas yang signifikan. Bayi dengan TTN baru lahir yang mebaik selama periode 24-jam untuk 72-jam.
• Tidak ada predileksi ras telah dilaporkan. Risiko adalah sama di kedua pria dan wanita. Secara klinis, takipnea transien dari hadiah baru lahir sebagai gangguan pernapasan pada bayi penuh panjang atau jangka pendek.

Manifestasi Klinis

• Riwayat ibu dari Bayi baru lahir dengan TTN harus dicermati saat prenatal dan persalinan  caesar
• Riwayat kehamilan ibu dengan Bayi baru lahir dengan TTN sering mengalami tendangan bayi yang sangat kuat terutama saat malam hari
• Tanda-tanda gangguan pernapasan (misalnya, takipnea, nasal flaring, grunting, retraksi, sianosis dalam kasus yang ekstrim) menjadi jelas segera setelah lahir.
• Kelainan ini memang sementara, dengan resolusi biasanya terjadi dalam waktu 72 jam setelah lahir.

Pemeriksaan Fisik

• Temuan fisik yang didapatkan Bayi baru lahir dengan TTN  meliputi takipnea dengan grunting, flaring, and retraksi.
• Bayi sering digambarkan sebagai memiliki  ”quiet” tachypnea “
• Kasus yang ekstrim dapat memperlihatkan sianosis.
• Sebuah studi yang menyelidiki faktor risiko untuk durasi takipnea pada pasien dengan takipnea transient yang baru lahir melaporkan bahwa tingkat pernapasan puncak lebih dari 90 napas per menit selama 36 jam pertama kehidupan dikaitkan dengan takipnea berkepanjangan yang berlangsung lebih dari 72 jam.

Penyebab

• Penyebab utama adalah gangguan penyerapan tertunda cairan paru
• Bayi baru lahir dengan TTN umumnya diamati kelahiran kelahiran sesar. • Sesar pengiriman
• Studi menggunakan pengukuran paru mekanik dilakukan pada bayi yang lahir dengan baik sesar atau pengiriman vagina. Milner dkk mencatat bahwa volume gas rata-rata toraks adalah 32,7 mL / kg pada bayi yang lahir melalui vagina dan 19,7 ml / kg pada bayi yang lahir melalui kelahiran sesar. Yang penting, lingkar dada adalah sama. Milner dkk mencatat bahwa bayi yang lahir melalui kelahiran sesar memiliki volume yang lebih tinggi dari cairan interstitial dan alveolar dibandingkan dengan mereka yang lahir melalui vagina, meskipun volume toraks secara keseluruhan berada dalam kisaran referensi.
• Pengeluaran Epinefrin selama persalinan mempengaruhi cairan paru janin. Dalam menghadapi tingkat epinefrin tinggi, pompa klorida bertanggung jawab untuk sekresi cairan paru-paru dihambat, dan saluran natrium yang menyerap cairan dirangsang. Akibatnya, gerakan bersih cairan dari paru-paru ke interstitium terjadi. Oleh karena itu, pengiriman caesar tanpa tenaga kerja dan kurangnya berikutnya dari ledakan normal dalam kontra-regulasi hormon membatasi perjalanan cairan paru.
• Asma ibu dan merokok. Demissie dkk melakukan analisis kohort historis pada pengiriman hidup tunggal di rumah sakit Jersey Baru dari 1989-1992. Bayi dari ibu yang menderita asma lebih mungkin untuk menunjukkan takipnea sementara. yang baru lahir dari bayi dari ibu pada kelompok kontrol.
• Schatz dkk mempelajari sekelompok 294 wanita hamil dengan asma dan sekelompok 294 wanita hamil tanpa asma. Kedua kelompok memiliki hasil tes fungsi normal paru dan yang cocok untuk usia dan status merokok. takipnea transient yang baru lahir ditemukan di 11 bayi (3,7%) dari ibu dengan asma dan dalam 1 bayi (0,3%) dari seorang ibu dari kelompok kontrol. Tidak ada perbedaan yang signifikan antara subyek kontrol asma dan dicocokkan di takipnea transient lain dari faktor risiko baru lahir diamati.
• Penelitian cohort menunjukkan bahwa Bayi baru lahir dengan TTN akan mengalami resiko asma yang sangat bermakna pada usia pra sekolah
• Seks pria dan makrosomia: Ini juga dikaitkan dengan peningkatan risiko takipnea transient yang baru lahir.
• Faktor-faktor lain: sedasi berlebihan ibu, asfiksia perinatal, dan kelahiran sesar pilihan tanpa kerja sebelumnya ini sering berhubungan dengan takipnea transient yang baru lahir.

Diagnosis Banding

• Congenital Pneumonia
• Meconium Aspiration Syndrome
• Neonatal Sepsis
• Pneumomediastinum
• Pneumothorax
• Pulmonary Hypertension, Persistent-Newborn
• Respiratory Distress Syndrome

Dignosis dan Pemeriksaan
Pemeriksaan laboratorium
Analisa Gas Darah (AGD)

• Penilaian AGD penting untuk memastikan tingkat pertukaran gas dan keseimbangan asam-basa.
• Pertimbangkan kateter intraarterial, seperti kateter arteri umbilikalis, jika fraksi terinspirasi bayi oksigen melebihi 40%.
• Hipoventilasi sangat jarang, dan ketegangan karbon dioksida parsial biasanya normal karena takipnea tersebut. Namun, meningkatnya karbon dioksida ketegangan pada bayi dengan takipnea mungkin tanda kegagalan pernapasan dan kelelahan yang akan datang atau komplikasi seperti pneumotoraks.

Pulse Oksimetri

• Memantau bayi dengan oksimetri nadi untuk penilaian oksigenasi.
• Pulse Oksimetri memungkinkan untuk menyesuaikan tingkat terapi oksigen yang dibutuhkan untuk mempertahankan saturasi yang sesuai.

Pemeriksaan pencitraan
Radiografi dada

• Radiografi dada adalah standar diagnostik untuk Bayi baru lahir dengan TTN .
• Temuan karakteristik termasuk perihilar menonjol, yang berkorelasi dengan kendurnya sistem limfatik dengan cairan paru-paru dipertahankan, dan cairan dalam celah.
• Efusi pleura kecil dapat terlihat.
• Patchy Infiltrat atau gambaran infiltrat yang halus pada kedua lapang paru secara homogen dan tersebar merata
• Tindak lanjut radiografi dada mungkin diperlukan jika sejarah klinis menunjukkan sindroma aspirasi mekonium atau pneumonia neonatal atau jika memburuk Status pernapasan.

 

Sebuah foto toraks anteroposterior terlentang Bayi baru lahir dengan TTN. Perhatikan penampilan retikuler atau patchy Infiltrat atau gambaran infiltrat yang halus pada kedua lapang paru secara homogen dan tersebar meratadengan cairan interstisial ringan kardiomegali

Penanganan

• Perawatan medis dari takipnea transient yang baru lahir (TTN) adalah terapi suportif.
• Cairan paru-paru tetap diserap oleh sistem limfatik bayi, status paru membaik.
• Perawatan suportif termasuk cairan intravena dan gavage menyusui sampai tingkat pernapasan mengalami penurunan cukup untuk memungkinkan pemberian makan oral.
• Oksigen tambahan untuk mempertahankan saturasi oksigen arteri memadai, pemeliharaan thermoneutrality, dan lingkungan stimulasi minimal adalah terapi yang diperlukan pada bayi ini. Penilaian AGD harus diulang secara berkala, terutama jika kondisi memburuk bayi. Demikian pula, radiografi dada harus diulang jika dekompensasi klinis diamati.
• Perbaikan klinis Bayi baru lahir dengan TTN adalah sesak bayi membaik, kebutuhan oksigen berkurang, dan radiografi dada menunjukkan resolusi dari goresan perihilar.
• Bayi baru lahir dengan TTN mungkin memiliki tanda-tanda yang terakhir dari beberapa jam sampai beberapa hari. Jarang, bayi mempunyai gambaran memburuk gangguan pernapasan setelah beberapa hari. Bila ini terjadi mungkin membutuhkan dukungan lebih agresif termasuk penggunaan continuous positive airway pressure (CPAP) atau ventilasi mekanis.
• Sebuah uji klinis menunjukkan peran epinefrin inhalasi untuk pengobatan takipnea transient yang baru lahir tidak menemukan dampak positif ketika epinefrin inhalasi diberikan untuk penuh panjang bayi baru lahir dengan sedang sampai berat takipnea transient yang baru lahir.  Lebih penting , mereka tidak mendeteksi perbedaan dalam tingkat resolusi takipnea di plasebo dan kelompok epinefrin inhalasi. Pada saat ini, epinefrin inhalasi tidak dianjurkan untuk Bayi baru lahir dengan TTN
• Konsultasi  Bayi baru lahir dengan TTN kadang-kadang mungkin memerlukan konsultasi dengan seorang neonatologist. Pertimbangkan konsultasi ini jika fraksi oksigen inspirasi melebihi 40%, jika asidosis metabolik atau asidosis pernafasan hadir, jika CPAP atau mekanik ventilasi diperlukan, jika bayi mulai menampilkan kelelahan (pernapasan periodik atau apnea), atau jika bayi gagal meningkatkan pada usia 48-72 jam.
• Diet Bayi baru lahir dengan TTN umumnya harus didukung oleh cairan intravena atau intra gastrik. Bayi dengan gangguan motilitas usus yang tidak baik mungkin  membutuhkan terapi intravena.
• Pemberian makan oral ditunda saat respirasi masih meningkat.

Medikasi Obat

• Penggunaan obat dalam Bayi baru lahir dengan TTN sangat  minimal.
• Antibiotik empiris sering digunakan selama 48 jam setelah lahir, sampai sepsis telah dikesampingkan.
• Antibiotik Antibiotika digunakan ketika didapatkan tanda dan gejala awal sepsis. Antibiotik umumnya adalah ampisilin dan aminoglikosida (gentamisin). Pilihan didasarkan pada flora lokal dan kepekaan antibiotik. Dosis jumlah dan interval didasarkan pada usia postmenstrual (PMA), diukur dalam minggu, dan usia pasca melahirkan, diukur dalam hari.
• Ampisilin (Omnipen-N) Sebuah antibiotik dengan aktivitas terhadap gram positif dan beberapa bakteri gram negatif. Ampisilin mengikat terhadap penisilin-mengikat protein (PBPs), menghambat pertumbuhan sel dinding bakteri.
• gentamisin MBekerja melawan  gram negatif cakupan aerobik. Gentamisin juga menyediakan aktivitas sinergis dengan penisilin terhadap bakteri gram positif termasuk kelompok B Streptococcus dan Enterococcus. Gentamisin menghambat sintesis protein oleh ireversibel mengikat 30S bakteri dan ribosom 50S.
  Diberikan sebagai infus IV dengan pompa alat suntik lebih 30 menit. Administer sebagai infus terpisah dari penisilin yang mengandung senyawa. IM injeksi dikaitkan dengan faktor penyerapan, terutama pada bayi VLBW.
• Diuretik belum terbukti bermanfaat.

Cold-formed steel (CFS) is the common term for products made by rolling or pressing thin gauges of sheet steel into goods. Cold-formed steel goods are created by the working of sheet steel using stamping, rolling, or presses to deform the sheet into a usable product. Cold worked steel products are commonly used in all areas of manufacturing of durable goods like appliances or automobiles but the phrase cold form steel is most prevalently used to described construction materials. The use of cold-formed steel construction materials has become more and more popular since its initial introduction of codified standards in 1946. In the construction industry both structural and non-structural elements are created from thin gauges of sheet steel. These building materials encompass columns, beams, joists, studs, floor decking, built-up sections and other components. Cold-formed steel construction materials differ from other steel construction materials known as hot-rolled steel (see structural steel). The manufacturing of cold-formed steel products occurs at room temperature using rolling or pressing. The strength of elements used for design is usually governed by buckling. The construction practices are more similar to timber framing using screws to assemble stud frames.

Cold-formed steel building

Cold-formed steel members have been used in buildings, bridges, storage racks, grain bins, car bodies, railway coaches, highway products, transmission towers, transmission poles, drainage facilities, various types of equipment and others.^[1] These types of sections are cold-formed from steel sheet, strip, plate, or flat bar in roll forming machines, by press brake (machine press) or bending operations. The material thicknesses for such thin-walled steel members usually range from 0.0147 in. (0.373 mm) to about ¼ in. (6.35 mm). Steel plates and bars as thick as 1 in. (25.4 mm) can also be cold-formed successfully into structural shapes (AISI, 2007b).^[2]

Contents 1 History of cold-formed steel 2 History of AISI design standards 3 International codes and standards 4 Common section profiles and applications 5 Typical stress–strain properties 6 Ductility criteria 7 Weldability 7.1 Minimum material thickness recommended for welding connections 8 Application in buildings 8.1 Cold-formed steel framing 8.2 Connectors and fasteners in framing 9 Hot-rolled versus cold-rolled steel and the influence of annealing 10 Alternative design methods 11 References 12 External links 12.1 Organizations

History of cold-formed steel

The use of cold-formed steel members in building construction began in the 1850s in both the United States and Great Britain. In the 1920s and 1930s, acceptance of cold-formed steel as a construction material was still limited because there was no adequate design standard and limited information on material use in building codes. One of the first documented uses of cold-formed steel as a building material is the Virginia Baptist Hospital [1], constructed around 1925 in Lynchburg, Virginia. The walls were load bearing masonry, but the floor system was framed with double back-to-back cold-formed steel lipped channels. According to Chuck Greene, P.E of Nolen Frisa Associates [2], the joists were adequate to carry the initial loads and spans, based on current analysis techniques. Greene engineered a recent renovation to the structure and said that for the most part, the joists are still performing well. A site observation during this renovation confirmed that "these joists from the 'roaring twenties' are still supporting loads, over 80 years later!" In the 1940s, Lustron Homes built and sold almost 2500 steel-framed homes, with the framing, finishes, cabinets and furniture made from cold-formed steel.

History of AISI design standards

Design standards for hot-rolled steel (see structural steel) were adopted in 1930s, but were not applicable to cold–formed sections because of their relatively thin steel walls which were susceptible to buckling. Cold-formed steel members maintain a constant thickness around their cross-section, whereas hot-rolled shapes typically exhibit tapering or fillets. Cold-formed steel allowed for shapes which differed greatly from the classical hot-rolled shapes. The material was easily workable; it could be deformed into many possible shapes. Even a small change in the geometry created significant changes in the strength characteristics of the section. It was necessary to establish some minimum requirements and laws to control the buckling and strength characteristics. Also it was observed that the thin walls underwent local buckling under small loads in some sections and that these elements were then capable of carrying higher loads even after local buckling of the members.
In the United States, the first edition of the Specification for the Design of Light Gage Steel Structural Members was published by the American Iron and Steel Institute (AISI) in 1946 (AISI, 1946).^[3] The first Allowable Stress Design (ASD) Specification was based on the research work sponsored by AISI at Cornell University under the direction of late Professor George Winter [3] since 1939.^[4] As a result of this work, George Winter is now considered the grandfather of cold-formed steel design. The ASD Specification was subsequently revised in 1956, 1960, 1962, 1968, 1980, and 1986 to reflect the technical developments and the results of continued research at Cornell and other universities (Yu et al., 1996).^[5] In 1991, AISI published the first edition of the Load and Resistance Factor Design Specification developed at University of Missouri of Rolla and Washington University under the directions of Wei-Wen Yu [4] and Theodore V. Galambos (AISI, 1991).^[6] Both ASD and LRFD Specifications were combined into a single specification in 1996 (AISI, 1996).^[7]
In 2001, the first edition of the North American Specification for the Design of Cold-Formed Steel Structural Members was developed by a joint effort of the AISI Committee on Specifications, the Canadian Standards Association (CSA) Technical Committee on Cold-Formed Steel Structural Members, and Camara Nacional de la Industria del Hierro y del Acero (CANACERO) in Mexico (AISI, 2001).^[8] It included the ASD and LRFD methods for the United States and Mexico together with the Limit States Design (LSD) method for Canada. This North American Specification has been accredited by the American National Standard Institute (ANSI) as an ANSI Standard to supersede the 1996 AISI Specification and the 1994 CSA Standard. Following the successful use of the 2001 edition of the North American Specification for six years, it was revised and expanded in 2007.^[9]
This updated specification includes new and revised design provisions with the additions of the Direct Strength Method in Appendix 1 and the Second-Order Analysis of structural systems in Appendix 2.
In addition to the AISI specifications, the American Iron and Steel Institute has also published commentaries on various editions of the specifications, design manuals, framing design standards, various design guides, and design aids for using cold-formed steel. For details, see AISI [5] website.

International codes and standards

The United States, Mexico and Canada use the North American Specification for the Design of Cold-Formed Steel Structural Members, document number AISI S100-2007. Member states of the European Union use section 1-3 of the Eurocode 3 (EN 1993) for the design of cold formed steel members. Other nations utilize various design specifications, many based on AISI S-100, as adopted by the building codes listed below. Another list of international cold-formed steel codes and standards is maintained (and can be edited with permission) at Cold-Formed Steel Codes Around the World.

Africa

Ethiopia Building Codes: EBCS-1 Basis of design and actions on structures EBCS-3 Design of steel structures
South Africa Specification: SANS 10162 - The Structural Use of Steel: Part 2 - Limit-state design of cold-formed steelwork Building code: National Building Regulations of South Africa

Americas

United States Specification: North American Specification for the Design of Cold-Formed Steel Structural Members, document number AISI S100-2007 published by the American Iron and Steel Institute in October 2007. Building Code: IBC and/or NFPA may be enforced, but both reference AISI S100.
Canada Specification: North American Specification for the Design of Cold-Formed Steel Structural Members, document number CAN/CSA S136-07 as published by Canadian Standards Association which is the same as AISI S100 except for the cover. Building Code: The National Building Code of Canada is the model code adopted with amendments by individual Provinces and Territories. The Federal government is outside the jurisdiction of the Provincial/Territorial authority but usually defers to the legislated requirements within the Province/Territory of the building site.
Brazil Specification: NBR 14762:2001 Dimensionamento de estruturas de aço constituídas por perfis formados a frio - Procedimento (Cold-formed steel design - Procedure, last update 2001) and NBR 6355:2003 Perfis estruturais de aço formados a frio - Padronização (Cold-formed steel structural profiles, last update 2003) Building Code: ABNT - Associação Brasileira de Normas Técnicas (www.abnt.org.br)
Chile NCH 427 - suspended because it was written in the 1970s. Cold-formed steel sections were based in part on AISI (U.S). The local Institute for Building code INN has specified in recent Codes for seismic design that designers must use the last edition of the AISI Specification for cold formed steel and the AISC for hot rolled, in their original versions in English until some traduced adaption will be issued here .
Argentina CIRSOC 303 for Light Steel Structures where cold formed steel is included. That Specification, now more than 20 years old, is being replaced by a new one, which will be, in general, an adaption of the current AISI one. The former CIRSOC 303 was an adaption of the Canadian code of that time. At this time CIRSOC 303 was very old, now CIRSOC 301 is in revition to be aligned with the American codes (LRFD design). In the near future both codes will be aligned also in designations and therminology.

Asia

Philippines National Structural Code of the Philippines (NSCP) 2010, Volume 1 Buildings, Towers, and other Vertical Structures, Chapter 5 Part 3 Design of Cold-Formed Steel Structural Members is based on AISI S100-2007
India Specification:IS:801, Indian standard code of practice for use of cold-formed light gauge steel structural members in general building construction, Bureau of Indian Standards, New Delhi (1975). (currently under revision) Building Code : see - model code National Building Code of India
China Specification: Technical Code of Cold-formed Thin-wall Steel Structures Building Code: GB 50018-2002 (current version)
Japan Specification: Design Manual of Light-gauge Steel Structures Building Code: Technical standard notification No.1641 concerning light-gauge steel structures
Malaysia Malaysia uses British Standard BS5950, especially BS5950:Part 5; AS4600 (from Australia) is also referenced.

Europe

EU Countries Specification: EN 1993-1-3 (same as Eurocode 3 part 1-3), Design of steel structures - Cold formed thin gauge members and sheeting. Each European country will get its own National Annex Documents (NAD).
Germany Specification: German Committee for Steel Structures (DASt), DASt-Guidelines 016: 1992: Calculation and design of structures with thin-walled cold-formed members; In German Building Code: EN 1993-1-3: 2006 (Eurocode 3 Part 1-3): Design of steel structures – General rules – Supplementary rules for cold-formed members and sheeting; German version prEN 1090 2: 2005 (prEN 1090 Part 2; Draft): Execution of steel structures and aluminium structures – Technical requirements for the execution of steel structures; German version EN 10162: 2003: Cold-rolled steel sections – Technical delivery conditions – Dimensional and cross-sectional tolerances; German version
Italy Specification: UNI CNR 10022 (National Document) EN 1993-1-3 (Not compulsory)
United Kingdom Eurocode for cold-formed steel in the UK. BS EN 1993-1-3:2006: Eurocode 3. Design of steel structures. General rules.

Oceania

Australia Specification: AS/NZS 4600 AS/NZS 4600:2005 Similar to NAS 2007 but includes high strength steels such as G550 for all sections. (Greg Hancock) Building Code: Building Code of Australia (National document) calls AS/NZS 4600:2005
NewZealand Specification: AS/NZS 4600 (same as Australia)

Common section profiles and applications

In building construction there are basically two types of structural steel: hot-rolled steel shapes and cold-formed steel shapes. The hot rolled steel shapes are formed at elevated temperatures while the cold-formed steel shapes are formed at room temperature. Cold-formed steel structural members are shapes commonly manufactured from steel plate, sheet metal or strip material. The manufacturing process involves forming the material by either press-braking or cold roll forming to achieve the desired shape.
When steel is formed by press-braking or cold rolled forming, there is a change in the mechanical properties of the material by virtue of the cold working of the metal. When a steel section is cold-formed from flat sheet or strip the yield strength, and to a lesser extent the ultimate strength, are increased as a result of this cold working, particularly in the bends of the section.
Some of the main properties of cold formed steel are as follows:^[10]

• Lightness in weight
• High strength and stiffness
• Ease of prefabrication and mass production
• Fast and easy erection and installation
• Substantial elimination of delays due to weather
• More accurate detailing
• Non shrinking and non creeping at ambient temperatures
• No formwork needed
• Termite-proof and rot proof
• Uniform quality
• Economy in transportation and handling
• Non combustibility
• Recyclable material
• Panels and decks can provide enclosed cells for conduits.

---

A broad classification of the cold-formed shapes used in the construction industry can be made as individual structural framing members or panels and decks.
Some of the popular applications and the preferred sections are:

• Roof and wall systems (industrial, commercial, and agricultural buildings)
• Steel racks for supporting storage pallets
• Structural members for plane and space trusses
• Frameless Stressed skin structures: Corrugated sheets or sheeting profiles with stiffened edges are used for small structures up to a 30 ft clear span with no interior framework

• 

  CFS Decking
  
• 

  CFS purlins
  
• 

  CFS X-braced wall system
  
• 

  CFS stud/girt wall connection
  

The AISI Specification allows the use of steel to the following ASTM specifications in the table below:^[11]

Steel Designation	ASTM Designation	Product	Yield Strength Fy (ksi)	Tensile Strength Fu (ksi)	Fu / Fy	Minimum Elongation (%) in 2-in. Gage Length
Carbon structural steel	A36		36	58-80	1.61	23
	A36		50	70	1.4	21
High-strength low-alloy Structural steel	A242		46	67	1.46	21
Low and intermediate tensile strength carbon steel plates	A283
	A		24	45-60	1.88	30
	B		27	50-65	1.85	28
	C		30	55-75	1.83	25
	D		33	60-80	1.82	23
Cold-formed welded and seamless carbon steel structural tubing in rounds and shapes	A500	Round Tubing
	A		33	45	1.36	25
	B		42	58	1.38	23
	C		46	62	1.35	21
	D		36	58	1.61	23
		Shape Tubing
	A		39	45	1.15	25
	B		46	58	1.26	23
	C		50	62	1.24	21
	D		36	58	1.61	23
High-strength carbon–manganese steel	A529 Gr. 42		42	60-85	1.43	22
	A529 Gr. 50		50	70-100	1.40	21
Hot-rolled carbon steel sheets and strips of structural quality	A570
	Gr. 30		30	49	1.63	21
	Gr. 33		33	52	1.58	18
	Gr. 36		36	53	1.47	17
	Gr. 40		40	55	1.38	15
	Gr. 45		45	60	1.33	13
	Gr. 50		50	65	1.30	11
High-strength low-alloy columbium– vanadium steels of structural quality	A572
	Gr. 42		42	60	1.43	24
	Gr. 50		50	65	1.30	21
	Gr. 60		60	75	1.25	18
	Gr. 65		65	80	1.23	17
High-strength low-alloy structural steel with 50 ksi minimum yield point	A588		50	70	1.40	21
Hot-rolled and cold-rolled high-strength low-alloy steel sheet and strip with improved corrosion resistance	A606	Hot-rolled as rolled cut length	50	70	1.40	22
		Hot-rolled as rolled coils	45	65	1.44	22
		Hot-rolled annealed	45	65	1.44	22
		Cold-rolled	45	65	1.44	22
Hot-rolled and cold-rolled high-strength low-alloy columbium and/or vanadium steel sheet and strip	A607 Class I
	Gr.45		45	60	1.33	Hot rolled (23) Cold rolled (22)
	Gr.50		50	65	1.30	Hot rolled (20) Cold rolled (20)
	Gr.55		55	70	1.27	Hot rolled (18) Cold rolled (18)
	Gr.60		60	75	1.25	Hot rolled (16) Cold rolled (16)
	Gr.65		65	80	1.23	Hot rolled (14) Cold rolled (15)
	Gr.70		70	85	1.21	Hot rolled (12) Cold rolled (14)
	A607 Class II
	Gr.45		45	55	1.22	Hot rolled (23) Cold rolled (22)
	Gr.50		50	60	1.20	Hot rolled (20) Cold rolled (20)
	Gr.55		55	65	1.18	Hot rolled (18) Cold rolled (18)
	Gr.60		60	70	1.17	Hot rolled (16) Cold rolled (16)
	Gr.65		65	75	1.15	Hot rolled (14) Cold rolled (15)
	Gr.70		70	80	1.14	Hot rolled (12) Cold rolled (14)
Cold-rolled carbon structural steel sheet	A611
	A		25	42	1.68	26
	B		30	45	1.50	24
	C		33	48	1.45	22
	D		40	52	1.30	20
Zinc-coated or zinc-iron alloy-coated steel sheet	A653 SS
	Gr. 33		33	45	1.36	20
	Gr. 37		37	52	1.41	18
	Gr. 40		40	55	1.38	16
	50 Class 1		50	65	1.30	12
	50 Class 3		50	70	1.40	12
	HSLAS Type A
	50		50	60	1.20	20
	60		60	70	1.17	16
	70		70	80	1.14	12
	80		80	90	1.13	10
	HSLAS Type B
	50		50	60	1.20	22
	60		60	70	1.17	18
	70		70	80	1.14	14
	80		80	90	1.13	12
Hot-rolled and cold-rolled high-strength low-alloy steel sheets and strip with improved formability	A715
	Gr. 50		50	60	1.20	22
	Gr. 60		60	70	1.17	18
	Gr. 70		70	80	1.14	14
	Gr. 80		80	90	1.13	12
55% aluminum-zinc alloy-coated steel sheet by the hot-dip process	A792
	Gr. 33		33	45	1.36	20
	Gr. 37		37	52	1.41	18
	Gr. 40		40	55	1.38	16
	Gr. 50A		50	65	1.30	12
Cold-formed welded and seamless high-strength, low-alloy structural tubing with improved atmospheric corrosion resistance	A847		50	70	1.40	19
Zinc-5% aluminum alloy-coated steel sheet by the hot-dip process	A875 SS
	Gr. 33		33	45	1.36	20
	Gr. 37		37	52	1.41	18
	Gr. 40		40	55	1.38	16
	50 Class 1		50	65	1.30	12
	50 Class 3		50	70	1.40	12
	HSLAS Type A
	50		50	60	1.20	20
	60		60	70	1.17	16
	70		70	80	1.14	12
	80		80	90	1.13	10
	HSLAS Type B
	50		50	60	1.20	22
	60		60	70	1.17	18
	70		70	80	1.14	14
	80		80	90	1.13	12

Typical stress–strain properties

A main property of steel, which is used to describe its behavior, is the stress–strain graph. The stress–strain graphs of cold-formed steel sheet mainly fall into two categories. They are sharp yielding and gradual yielding type illustrated below in Fig.1 and Fig.2, respectively.

These two stress–strain curves are typical for cold-formed steel sheet during tension test. The second graph is the representation of the steel sheet that has undergone the cold-reducing (hard rolling) during manufacturing process, therefore it does not exhibit a yield point with a yield plateau. The initial slope of the curve may be lowered as a result of the prework. Unlike Fig.2, the stress–strain relationship in Fig.1 represents the behavior of annealed steel sheet. For this type of steel, the yield point is defined by the level at which the stress–strain curve becomes horizontal.
Cold forming has the effect of increasing the yield strength of steel, the increase being the consequence of cold working well into the strain-hardening range. This increase is in the zones where the material is deformed by bending or working. The yield stress can be assumed to have been increased by 15% or more for design purposes. The yield stress value of cold-formed steel is usually between 33ksi and 80ksi. The measured values of Modulus of Elasticity based on the standard methods usually range from 29,000 to 30,000 ksi (200 to 207 GPa). A value of 29,500 ksi (203 GPa) is recommended by AISI in its specification for design purposes. The ultimate tensile strength of steel sheets in the sections has little direct relationship to the design of those members. The load-carrying capacities of cold-formed steel flexural and compression members are usually limited by yield point or buckling stresses that are less than the yield point of steel, particularly for those compression elements having relatively large flat-width ratios and for compression members having relatively large slenderness ratios. The exceptions are bolted and welded connections, the strength of which depends not only on the yield point but also on the ultimate tensile strength of the material. Studies indicate that the effects of cold work on formed steel members depend largely upon the spread between the tensile and the yield strength of the virgin material.

Ductility criteria

Ductility is defined as ‘‘an extent to which a material can sustain plastic deformation without rupture.’’ It is not only required in the forming process but is also needed for plastic redistribution of stress in members and connections, where stress concentration would occur. The ductility criteria and performance of low-ductility steels for cold-formed members and connections have been studied by Dhalla, Winter, and Errera at Cornell University. It was found that the ductility measurement in a standard tension test includes local ductility and uniform ductility. Local ductility is designated as the localized elongation at the eventual fracture zone. Uniform ductility is the ability of a tension coupon to undergo sizeable plastic deformations along its entire length prior to necking. This study also revealed that for the different ductility steels investigated, the elongation in 2-in. (50.8-mm) gage length did not correlate satisfactorily with either the local or the uniform ductility of the material. In order to be able to redistribute the stresses in the plastic range to avoid premature brittle fracture and to achieve full net-section strength in a tension member with stress concentrations, it is suggested that:

• The minimum local elongation in a - 1–2 in. (12.7-mm) gauge length of a standard tension coupon including the neck be at least 20%.
• The minimum uniform elongation in a 3-in. (76.2-mm) gauge length minus the elongation in a 1-in. (25.4-mm) gage length containing neck and fracture be at least 3%.
• The tensile-strength-to-yield-point ratio Fu /Fy be at least 1.05.

Weldability

Weldability refers to the capacity of steel to be welded into a satisfactory, crack free, sound joint under fabrication conditions without difficulty.^[1] Welding is possible in cold-formed steel elements, but it shall follow the standards given in AISI S100-2007, Section E.
1.When thickness less than or equal to 3/16” (4.76mm):
The various possible welds in cold formed steel sections, where the thickness of the thinnest element in the connection is 3/16” or less are as follows

• • Groove Welds in Butt joints
  • Arc Spot Welds
  • Arc Seam Welds
  • Fillet Welds
  • Flare Groove Welds

2.When thickness greater than or equal to 3/16” (4.76mm):
Welded connections in which thickness of the thinnest connected arc is greater than 3/16” (4.76mm) shall be in accordance with ANSI/AISC-360. The weld positions are covered as per AISI S100-2007 (Table E2a)^[9]

Minimum material thickness recommended for welding connections

Application	Shop or Field fabrication	Electrode method	Suggested minimum CFS thickness
CFS to Structural steel	Field-fabrication	Stick-welding	54 mils to 68 mils
CFS to Structural steel	Shop-fabrication	Stick-welding	54 mils to 68 mils
CFS to CFS	Field-fabrication	Stick-welding	54 mils to 68 mils
CFS to CFS	Field-fabrication	Wire-fed MIG (Metal Inert Gas) welding	43 mils to 54 mils
CFS to CFS	Shop-fabrication	Wire-fed MIG (Metal Inert Gas) welding	33 mils

^[12]

Application in buildings

Cold-formed steel framing

Cold-formed steel framing (CFSF) refers specifically to members in light-frame building construction that are made entirely of sheet steel, formed to various shapes at ambient temperatures. The most common shape for CFSF members is a lipped channel, although “Z”, “C”, tubular, “hat” and other shapes and variations have been used. The building elements that are most often framed with cold-formed steel are floors, roofs, and walls, although other building elements and both structural and decorative assemblies may be steel framed.
Although cold-formed steel is used for several products in building construction, framing products are different in that they are typically used for wall studs, floor joists, rafters, and truss members. Examples of cold-formed steel that would not be considered framing includes metal roofing, roof and floor deck, composite deck, metal siding, and purlins and girts on metal buildings.
Framing members are typically spaced at 16 or 24 inches on center, with spacing variations lower and higher depending upon the loads and coverings. Wall members are typically vertical lipped channel “stud” members, which fit into unlipped channel “track” sections at the top and bottom. Similar configurations are used for both floor joist and rafter assemblies, but in a horizontal application for floors, and a horizontal or sloped application for roof framing. Additional elements of the framing system include fasteners and connectors, braces and bracing, clips and connectors.
In North America, member types have been divided into five major categories, and product nomenclature is based on those categories.

• S members are lipped channels, most often used for wall studs, floor joists, and ceiling or roof rafters.
• T members are unlipped channels, which are used for top and bottom plates (tracks) in walls, and rim joists in floor systems. Tracks also form the heads and sills of windows, and typically cap the top and bottom of boxed- or back-to-back headers.
• U members are unlipped channels that have a smaller depth than tracks, but are used to brace members, as well as for ceiling support systems.
• F members are “furring” or “hat” channels, typically used horizontally on walls or ceilings.
• L members are angles, which in some cases can be used for headers across openings, to distribute loads to the adjacent jamb studs.

In high-rise commercial and multi-family residential construction, CFSF is typically used for interior partitions and support of exterior walls and cladding. In many mid-rise and low-rise applications, the entire structural system can be framed with CFSF.

Connectors and fasteners in framing

Connectors are used in cold-formed steel construction to attach members (i.e. studs, joists) to each other or to the primary structure for the purpose of load transfer and support. Since an assembly is only as strong as its weakest component, it is important to engineer each connection so that it meets specified performance requirements. There are two main connection types, Fixed and Movement-Allowing (Slip). Fixed connections of framing members do not allow movement of the connected parts. They can be found in axial-load bearing walls, curtain walls, trusses, roofs, and floors. Movement-Allowing connections are designed to allow deflection of the primary structure in the vertical direction due to live load, or in the horizontal direction due to wind or seismic loads, or both vertical and horizontal directions. One application for a vertical movement-allowing connection is to isolate non-axial load bearing walls (drywall) from the vertical live load of the structure and to prevent damage to finishes. If the structure is in an active seismic zone, vertical and horizontal movement-allowing connections may be used to accommodate both the vertical deflection and horizontal drift of the structure.
Connectors may be fastened to cold-formed steel members and primary structure using welds, bolts, or self-drilling screws. These fastening methods are recognized in the American Iron and Steel Institute (AISI) 2007 North American Specification for the Design of Cold-Formed Steel Structural Members, Chapter E. Other fastening methods, such as clinching, power actuated fasteners (PAF), mechanical anchors, adhesive anchors and structural glue, are used based on manufacturer's performance-based tests.

Hot-rolled versus cold-rolled steel and the influence of annealing

		Hot rolled	Cold rolled
Material properties	Yielding strength	The material is not deformed; there is no initial strain in the material, hence yielding starts at actual yield value as the original material.	The yield value is increased by 15%–30% due to prework (initial deformation).
	Modulus of elasticity	29,000 ksi	29,500 ksi
	Unit weight	Unit weight is comparatively huge.	It is much smaller.
	Ductility	More ductile in nature.	Less ductile.
Design		Most of the time, we consider only the global buckling of the member.	Local buckling, Distortional Buckling, Global Buckling have to be considered.
Main uses		Load bearing structures, usually heavy load bearing structures and where ductility is more important ( Example Seismic prone areas)	Application in many variety of loading cases. This includes building frames, automobile, aircraft, home appliances, etc. Use limited in cases where high ductility requirements.
Flexibility of shapes		Standard shapes are followed. High value of unit weight limits the flexibility of manufacturing wide variety of shapes.	Any desired shape can be molded out of the sheets. The light weight enhances its variety of usage.
Economy		High Unit weight increases the overall cost – material, lifting, transporting, etc. It is difficult to work with (e.g. connection).	Low unit weight reduces the cost comparatively. Ease of construction (e.g. connection).
Research possibilities		In the advanced stages at present.	More possibilities as the concept is relatively new and material finds wide variety of applications.

Annealing, also described in the earlier section, is part of the manufacturing process of cold-formed steel sheet. It is a heat treatment technique that alters the microstructure of the cold-reducing steel to recover its ductility.

Alternative design methods

The Direct Strength Method (DSM) is an alternative method of design located in Appendix 1 of the North American Specification for the Design of Cold-formed Steel Structural Members 2007 (AISI S100-07). DSM may be used in lieu of the Main Specification for determining nominal member capacities. Specific advantages include the absence of effective width and iterations, while only using known gross-sectional properties. An increase in prediction confidence stems from forced compatibility between section flanges and web throughout elastic buckling analysis. This increase in prediction accuracy for any section geometry provides a solid basis for rational analysis extension and encourages cross-sectional optimization. Either DSM or the main specification can be used with confidence as the Φ or Ω factors have been designed to insure that both methods are accurate. Currently, DSM only provides solutions for beams and columns and has to be used in conjunction with the main specification for a complete design.
Rational analysis is permitted when using optimized cold form shapes that are outside of the scope of the main specification and are not pre-qualified for DSM use. These non pre-qualified sections use the factors of safety of ϕ and Ω associated with rational analysis (see AISI 2001 Section A1.1 (b)). The result of the rational analysis times the appropriate factor of safety will be used as the design strength of the section.
Several situations may exist where a rational analysis application of DSM can be used. In general these would include: (1) determining the elastic buckling values and (2) using the DSM equations in Appendix 1 to determine nominal flexural and axial capacities, Mn and Pn. The premise of DSM itself is an example of rational analysis. It uses elastic buckling results to determine the ultimate strength through the use of empirical strength curves. This provides designers with a method for performing a rational analysis in a number of unique situations.
In some cases the rational analysis extension to DSM may be as simple as dealing with an observed buckling mode that is difficult to identify and making a judgment call as to how to categorize the mode. But it could also be used to allow an engineer to include the effects of moment gradients, the influence of different end conditions, or the influence of torsion warping on all buckling modes.
There are currently no provisions within the DSM that pertain to shear, web crippling, holes in members, or strength increases due to the cold work of forming. Research on several of these topics has been completed or is in the process of being completed and should be included in the next update of the AISI Specification. DSM is also limited in determining strength for sections in which very slender elements are used. This is due to the strength of a cross section being predicted as a whole with DSM instead of using the effective width method of the specification which breaks the cross section up into several effective elements. One slender element will cause low strength with DSM, which is not the case with the current specification method. The finite strip method using CUFSM is the most commonly used approach to determine the elastic buckling loads. The program also limits DSM because holes cannot be considered, loads have to be uniform along the member, only simply supported boundary conditions are considered, and the buckling modes interact and cannot be easily distinguishable in some cases.

References

1. ^ ^{a b} Wei-Wen Yu, John Wiley and Sons Inc. (2000). Cold-Formed Steel Design. John Wiley & Sons, New York, NY.
2. ^ American Iron and Steel Institute, Commentary on North American Specification for the Design of Cold-Formed Steel Structural Members, Washington, D.C. Published 2007
3. ^ American Iron and Steel Institute, Specification for the Design of Light Gage Steel Structural Members, New York, N.Y., Published 1946
4. ^ Journal of the Structural Division, ASCE, Volume 85, No.ST9, Cold-Formed, Light Gage Steel Construction, Published 1959
5. ^ Yu, W.W., D.S. Wolford, and A.L. Johnson, Golden Anniversary of the AISI Specification, Proceedings of the 13th International Specialty Conference on Cold-Formed Steel Structures, St. Louis, MO., Published 1996
6. ^ American Iron and Steel Institute, Load and Resistance Factor Design Specification for Cold-Formed Steel Structural Members, Washington, D.C. Published 1991
7. ^ American Iron and Steel Institute, Specification for the Design of Cold-Formed Steel Structural Members, Washington, D.C. Published 1996
8. ^ American Iron and Steel Institute, North American Specification for the Design of Cold-Formed Steel Structural Members, Washington, D.C. Published 2001
9. ^ ^{a b} American Iron and Steel Institute (2007). North American Specification for the Design of Cold-Formed Steel Structural Members. Washington, D.C.
10. ^ Gregory J. Hancock, Thomas M. Murray, Duane S. Ellifritt, Marcel Dekker Inc., “Cold-Formed Steel Structures to the AISI Specification”, 2001
11. ^ ASTM Standard, “Iron and Steel Products”, Vol. 01.04, 2005
12. ^ Ide, Brian, S.E., P.E. and Allen, Don, P.E. SECB.Structural Engineer Magazine. September 2009. page 26

Daerah wisata yang layak dikunjungi di pulau Lombok

Kemanakah tujuan Anda, jika mempunyai kesempatan berkunjung ke pulau Lombok? Bila Anda belum mempunyai tujuan yang pasti, menurut teman yang tinggal di kota Mataram, dengan punya waktu 2 (dua) hari bisa mengunjungi seluruh daerah pariwisata di Lombok, tentunya minus mendaki gunung Rinjani atau menginap di pulau Gili Trawangan.
Peta pulau Lombok
Di bawah ini akan saya sampaikan beberapa daerah yang layak dikunjungi (walaupun saya juga belum sempat mengunjungi semuanya), sesuai brosur pariwisata yang saya peroleh dari hotel tempat saya menginap:
1. Suranadi. Di sini ada hotel lengkap dengan kolam renang air hangat dan lapangan tennis. Juga ada pura Hindu tertua, berlokasi 17 km jika naik kendaraan dari kota Mataram.
2. Lingsar. Pura dengan ikan keramat di dalam kolam, lokasi 9 km dengan naik kendaraan dari kota Mataram.
3. Narmada. Kebun Raya Lombok, dengan kolam renang, serta ada pura Hindu yang sering digunakan umat Hindu untuk bersembahyang, lokasi 12 km dengan kendaraan dari kota Mataram.
Menjelang matahari terbenam di Pura Batu Bolong, Lombok
4. Batu Bolong. Terdapat pura diatas batu karang yang menjorok ke laut, dan jika cuaca cerah bisa melihat gunung Agung di pulau Bali, serta bagus untuk melihat pemandangan saat sunset. Lokasi 8 km dengan kendaraan dari kota Mataram. Untuk memasuki area, maka kita diwajibkan memakai pita kuning dari kain (dapat menyewa di lokasi), yang dipasang melingkari pinggang. Pemandangan disini indah sekali, air laut menerobos melalui sela-sela batu karang yang berlubang, menimbulkan bunyi gemerosak. Sayang saat saya kesini, cuaca masih mendung selepas turun hujan, tapi pemandangan indah sekali. Matahari mengintip di sela-sela awan, dan cahayanya jatuh terpantul di air laut.

Mendung menjelang sunset di pantai Senggigi
5. Senggigi. Pantai alam berpasir putih yang bersih, dikelilingi hotel, losmen dan bungalow. Sangat indah sekali, terutama jika waktu sunrise maupun sunset. Lokasi 10 km dengan kendaraan dari kota Mataram. Di pantai banyak penjaja cinderamata, berupa mutiara budidaya air tawar yang berwarna warni, mulai dari harga Rp.25.000,- Juga penjaja kaos bertuliskan Lombok dan Senggigi, serta ukiran khas Lombok pada kayu, bisa berupa tempat buah, topeng dan lain-lain.
6. Sire Beach. Taman laut dengan exotic coral dan ikan yang berenang kian kemari. Berlokasi 36 km dengan kendaraan dari kota Mataram.
7. Gili Air, Gili Meno dan Gili Trawangan. Pulau kahyangan di utara Lombok, dikelilingi taman laut. Disini banyak orang diving maupun surfing. Di pulau ini sudah banyak hotel dan losmen, sehingga bisa menginap disini, pantainya masih asli. Untuk mencapai lokasi ini bisa menggunakan kapal motor.
8. Sukarare. Desa tempat orang menenun, disinilah jika ingin membeli kain tenun tradisional khas Lombok, serta melihat bagaimana para penenun melakukan pekerjaannya. Lokasi 25 km dengan kendaraan dari kota Mataram.
9. Rambitan/Sade. Desa asli Lombok, dengan rumah tradisional suku Sasak, lokasi 50 km dengan kendaraan dari kota Mataram.
10. Kuta/Tanjung Aan. Pantai Mandalika dengan lampu-lampu yang berkilauan , dimana kita bisa berenang, terdapat hotel dan restoran. Setiap tahun ada perayaan menangkap/melihat Nyale fish, lokasi 56 km dengan kendaraan dari kota Mataram.
11. Mataram. Mataram adalah ibu kota propinsi Nusa Tenggara Barat. Sedangkan Ampenan merupakan kota pelabuhan lama (sekarang sudah pindah ke Lembar). Kota Ampenan berciri khas arsitektur kuno, yang bila dibersihkan dan dirawat dengan baik, akan menjadi daerah tujuan wisata yang digemari. Di kota Mataram (yang sudah menjadi satu kesatuan dengan kota Ampenan dan kota Cakranegara) kita bisa wisata kuliner, dengan makan makanan Lombok yang ciri khasnya adalah pedas. Di Jakarta kita sering melihat rumah makan Taliwang, yang ternyata Taliwang adalah nama suatu daerah, yang awalnya banyak penjual makanan khas Lombok di daerah ini. Makanan khas Lombok, antara lain: Plecing kangkung, ayam plecingan, ayam julat (ayam yang bumbunya pedas sekali), sambel beberok. Plecing ternyata merupakan nama masakan, sehingga dikenal masakan kangkung yang diberi /dimasak bumbu plecing, ayam yang dimasak plecing (ayam diberi bumbu pedas, didiamkan, dibakar/digoreng, kemudian diberi bumbu pedas lagi). Sambel beberok adalah sambel yang dibuat dari irisan terong ungu, irisan bawang merah, irisan tomat dan cabe, disajikan bersama makanan khas Lombok lainnya. Minuman yang khas adalah kelapa madu, terdiri dari air kepala muda, dan kelapa mudanya di suwir-suwir serta diberi madu…ehhm…sedaaap. Untuk membeli oleh-oleh kain tenun khas Lombok, bisa di Cilinaya Shopping Centre.
12. Cakranegara. Merupakan kota bisnis, terdapat pasar pertanian, pasar burung, dan mata air Mayura serta pura Meru, pura terbesar di Lombok. Cakranegara konon dulunya merupakan bekas kerajaan, namun bekas kerajaan (situs) sudah tak bisa dikenali. Jika ingin oleh-oleh makanan, maka bisa membeli kaki ayam goreng, telur asin dan berbagai manisan dari rumput laut.
Catatan : Perjalanan ke kota Mataram, bisa ditempuh menggunakan pesawat terbang dari Jakarta. Jarak tempuh 4 jam jika transit di Yogya atau Surabaya, tapi bila langsung (penerbangan Garuda pagi hari dari bandara Selaparang) hanya ditempuh dalam waktu 1 jam 33 menit.

Pengalaman saya tinggal di Mataram ini nih hasil jepretannya

 

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Tempat Wisata di Pontianak dan Singkawang

LOKASI DI RINDU ALAM SINGKAWANG, Dari kota Pontianak kira-kira 4 jam disana terdapat pemandangan yang lumayan indah untuk dinikmati. Ini foto saya pada tanggal 19 september 2010 sama istri saya. Selama saya tinggal di pontianak selama 2 tahun baru ini tahu ada tempat wisata yang menakjubkan yang dapat dilihat dari puncak bukit pemandangan laut dan pantai sebelah barat kalimantan.

Ini foto saya di Tugu Katulistiwa Pontianak. Disini adalah titik equator yang terletak di Pontianak dan kalau mengunjungi kota Pontianak wajib datang ke tempat ini.