2. Construction Considerations BAB 8.pptx

Planning a commercial construction project is a complex process that requires careful thought, detailed preparation, and strategic decision-making. Whether you’re building a new office space, a retail storefront, or an manufacturing facility, understanding the key factors that influence the success of your project is crucial. At Empire Building Construction, we’ve helped countless clients navigate the intricacies of commercial construction. Here are our insights on the five key considerations you need to keep in mind when planning your project.

1. Construction C onsiderations Group 7 Chapter 8 AULIA NUR ROHMAH 2035201028 FIRDAUS AHMAD TOHIRIN 2035201030 ARDIANSYAH SETIA ANUGRAH 2035201031 DIANA PRAJNA PARAMITA 2035201033 PUTRI VIRA NIKMA AQILA 2035201034 FEBRINA SUGMA SAFITRI 2035201035 ADELLA DYAH AYU PRAMESTI 2035201036

2. STEEL FABRICATION AND CONCRETE CONSTRUCTION The design rules in AS 5100.6 (SA 2004) are valid for steel components that are fabricated in accordance to NZS 3404.1 (SNZ 2009), which includes specification of materials and of fabrication workmanship. All concrete components that are designed to NZS 3101 (SNZ 2006) shall be constructed in accordance to NZS 3109 (1997a). Note that proper curing of the concrete is crucial to the structural and durability performance of the concrete member. Therefore, the designer should ensure that the contractor meets the minimum requirements listed in NZS 3109 , which can be achieved by providing a financial incentive by stipulating the curing of the concrete as a separate item on the project contractual documents.

3. The construction sequence that needs to be evaluated for composite bridges is: 1. Completion of substructure (up to bearing level) 2. installation of structural steel (piece by piece) 3. Provision of formwork 4. casting deck plate 5. completion of construction and equipment such as barriers and drainage CONSTRUCTION SEQUENCE

4. In addition, there are stages of construction that need to be analyzed, namely a series of models of the partly completed structures are required for each stage. the construction methods such as launching and transportation from the structure section to completion. it has a local effect on the temporary support position and needs to be evaluated. The series of analytical models must represent the development of the composite structure at the time the plate member is cast. because the entire length of the deck at once is impractical to pour if the series does not represent the development of the structure The series of analytical models must represent the development of the composite structure at the time the plate member is cast. because the entire length of the deck at once is impractical to apply if the series of analytical models does not represent the development of the structure

5. GIRDER ERECTION Girder lengths are chosen to suit transportation for facilitate the moving and lifting process as the figure below 1.1 (see section 4.2.1 and Guide to heavy vehicle management (NZT 2006)). Although the weight of individual pieces may limit the size where crane access is restricted. Figure 1.1 Transporting bridge girder Strength verification during girder erection is unlikely to require detailed evaluation, but stability and buckling resistance do require careful consideration, particularly before bracing or cross girder are fully installed.

6. BRACING Bracing of the steelwork in the bare steel and partly complete stages is a key to the effective performance of the main girders. Several bracing schemes may need to be evaluated.

7. SLAB CONSTRUCTION Although deck slabs have traditionally been cast on temporary timber false work, the use of permanent formwork notably partial depth precast decking that forms part of the final slab is now very common (as on section 2.3). Timber false work is often supported off the bottom flanges of the girders; precast permanent formwork sits on the top flanges and thus needs to be considered as a destabilising load. Whichever type of formwork, the weight at the wet concrete stage imposes quite high stresses in the top langes of the girders. Their strength and stability at this stage require a detailed evaluation of the progressive changes in structural behaviour as load is added. The weight of the concrete cantilevers needs particular attention, because of the moment (about the longitudinal axis) that is imposed on the outer girder.

8. PATCH LOADING ON WEBS For girders that are erected by launching, reactions under the girder as it is progressively launched impose local ‘patch loading’ on the unstiffened portions of the main girder webs. The web will need to be checked for the effects of combined stresses and for buckling.

9. LOADING FORM CANTILEVER The use of precast units, especially partial depth precast decking, is the current popular method of cantilever construction. The moment due to weight of cantilevered false work and wet concrete is transferred to the main girder as a couple of horizontal forces at top and bottom flange levels; these forces cause horizontal bending of the flanges between restraint positions. This is in effect warping torsion, rather than St Venant torsion. In ladder deck bridges, the effects of warping are modest, because the cross girders provide restraint at close regular intervals; in multi girder decks the restraint positions are further apart and the effects are greater. Deflection at the restraint positions (due to the bending of cross girders or the vertical displacement of the main girders due to the eccentric moment) adds twisting effects. Warping stresses, distortional displacements and twists all need to be determined. Although the warping stresses (transverse bending stresses) in the top flanges are locked in once the concrete hardens, it is not necessary to include these effects for the in-service condition because at ULS they will redistribute and at SLS any relaxation would be unlikely to lead to any noticeable permanent deformation. The alternative method of constructing cantilevers is to add full thickness precast units once the central portion of the deck slab has been completed. Support for these units can be from overhead temporary frames on the deck and although the weight causes twist (because of differential deflection of the main girders); there are no warping effects in the main girders.

10. DESIGN OF CANTILEVER EDGE SLABS For multi-girder bridges, cantilever edge slabs are usually the last part of the deck slab to be concreted, in order to achieve a good alignment along this very visible feature. Their contribution to structural behaviour of the cantilevers cannot therefore be relied upon until a late stage during construction. The edge slabs of ladder deck bridges are usually concreted at the same time as the main deck slab.

11. ALLOWANCE FOR PERMANENT DEFORMATIONS The deflections under unfactored dead and superimposed loads should be calculated to enable the girders to be pre-cambered. This information should be produced by the designer and a breakdown of the effects of the various actions included on the drawings. Where staged construction has been presumed, the sequence should be stated on the drawings. A residual hogging profile is often specified, for aesthetic reasons, even when not needed to meet a clearance requirement at SLS. For the calculation of deflections of composite sections, it is necessary to assume an age at first loading, so that the appropriate parameters for concrete can be determined. The steelwork should normally be pre-cambered to offset the predicted deflection at the end of construction.