Composite Beam

BayzoniJurusan Teknik Sipil Fakultas Teknik

Universitas Lampung, 2012

STRUKTUR BAJA II

Lantai Jembatan

(a) One Raffles Link, Singapore (b) Cellform beam

The main advantages ofcombining the use of steel and concretematerials for building construction are:

Steel and concrete may be arranged to produce anideal combination of strength, with concreteefficient in compression and steel in tension

Composite systems are lighter in weight (about 20to 40% lighter than concrete construction). Becauseof their light weight, site erection and installationare easier, and thus labor costs can be minimized.Foundation costs can also be reduced.

Steel and concrete may be arranged to produce anideal combination of strength, with concreteefficient in compression and steel in tension

Composite systems are lighter in weight (about 20to 40% lighter than concrete construction). Becauseof their light weight, site erection and installationare easier, and thus labor costs can be minimized.Foundation costs can also be reduced.

The main advantages ofcombining the use of steel and concretematerials for building construction are: The construction time is reduced, since casting of additional floors may proceed

without having to wait for the previously cast floors to gain strength. The steeldecking system provides positive moment reinforcement for the composite floor,requires only small amounts of reinforcement to control cracking, and provides fireresistance

The construction of composite floors does not require highly skilled labor. The steeldecking acts as permanent formwork. Composite beams and slabs canaccommodate raceways for electrification, communication, and air distributionsystems. The slab serves as a ceiling surface to provide easy attachment of asuspended ceiling.

The composite slab, when fixed in place, can act as an effective in-planediaphragm, which may provide effective lateral bracing to beams.

Concrete provides corrosion and thermal protection to steel at elevatedtemperatures. Composite slabs of a 2-h fire rating can be easily achieved for mostbuilding requirements.

The construction time is reduced, since casting of additional floors may proceedwithout having to wait for the previously cast floors to gain strength. The steeldecking system provides positive moment reinforcement for the composite floor,requires only small amounts of reinforcement to control cracking, and provides fireresistance

The construction of composite floors does not require highly skilled labor. The steeldecking acts as permanent formwork. Composite beams and slabs canaccommodate raceways for electrification, communication, and air distributionsystems. The slab serves as a ceiling surface to provide easy attachment of asuspended ceiling.

The composite slab, when fixed in place, can act as an effective in-planediaphragm, which may provide effective lateral bracing to beams.

Concrete provides corrosion and thermal protection to steel at elevatedtemperatures. Composite slabs of a 2-h fire rating can be easily achieved for mostbuilding requirements.

The floor slab may be constructed by the following methods

Stress distributionin a composite cross section

Web opening with horizontalreinforcement

Composite castellated beams

Parallel composite beam system

Composite Trusses

Stub Girder System

KOMPONEN STRUKTUR KOMPOSIT(SNI)

Balok baja yang memikul pelat beton bertulangdan bekerja bersama-sama dengan pelat tersebutsebagai satu kesatuan dalam memikul lentur

Balok komposit sederhana atau menerus denganpenghubung geser; atau profil baja yang diberiselubung beton, baik yang dibangun dengan atautanpa penumpu sementara (perancah).

Balok baja yang memikul pelat beton bertulangdan bekerja bersama-sama dengan pelat tersebutsebagai satu kesatuan dalam memikul lentur

Balok komposit sederhana atau menerus denganpenghubung geser; atau profil baja yang diberiselubung beton, baik yang dibangun dengan atautanpa penumpu sementara (perancah).

Komponen struktur lentur

Lebar efektif pelat lantai yang membentang padamasing-masing sisi dari sumbu balok tidak bolehmelebihi:

a) Seperdelapan dari bentang balok (jarakantara tumpuan);

b) Setengah jarak bersih antara sumbubalok-balok yang bersebelahan;

c) Jarak ke tepi pelat.

Lebar efektif pelat lantai yang membentang padamasing-masing sisi dari sumbu balok tidak bolehmelebihi:

a) Seperdelapan dari bentang balok (jarakantara tumpuan);

b) Setengah jarak bersih antara sumbubalok-balok yang bersebelahan;

c) Jarak ke tepi pelat.

Kekuatan balok komposit denganpenghubung geser

Persyaratan untuk dek bajabergelombang

Persyaratan untuk dek bajabergelombang

Penghubung geser

Gaya geser horizontal

Kekuatan penghubung geser jenispaku

Kekuatan penghubung geser kanal

Jumlah penghubung geser yangdiperlukan

Jumlah penghubung geser yang diperlukan padadaerah yang dibatasi oleh titik-titik momen lenturmaksimum, positif atau negatif, dan momen nolyang berdekatan adalah sama dengan gaya geserhorizontal total yang bekerja

Jumlah penghubung geser yang diperlukan padadaerah yang dibatasi oleh titik-titik momen lenturmaksimum, positif atau negatif, dan momen nolyang berdekatan adalah sama dengan gaya geserhorizontal total yang bekerja

Penempatan dan jarak antarpenghubung geser

Kecuali ditentukan lain, penghubung geser yangdiperlukan pada daerah yang dibatasi oleh titik-titik momen lentur maksimum dan momen nol yangberdekatan harus didistribusikan secara meratapada daerah tersebut

Kecuali ditentukan lain, penghubung geser yangdiperlukan pada daerah yang dibatasi oleh titik-titik momen lentur maksimum dan momen nol yangberdekatan harus didistribusikan secara meratapada daerah tersebut

The nominal strength of a shear studconnector embedded in a solidconcrete slab may be computed from

When the shear connectors are embedded in concrete ona metal deck, a reduction factor R should be applied to Qn

When the ribs of the metal deck are perpendicularto the beam

When the ribs of the steel deck are parallel to thesteel beam and wr/hr < 1.5,

When the ribs of the metal deck are perpendicularto the beam

When the ribs of the steel deck are parallel to thesteel beam and wr/hr < 1.5,