Leveling shims carry the full construction load of the precast element and must provide adequate support to prevent movement until the element is incorporated in the main structure.Īll temporary propping requirements must be shown on the erection drawings. Leveling shims should be formed from a suitably durable material and should have adequate strength to carry the full imposed loads.
Precast concrete elements must be adequately braced and supported during all phases of erection to ensure proper alignment and structural integrity until permanent structural connections are completed. Headroom availability and maneuverability during erection may also have an impact on the type of rigging system selected. The selection of such components should take into consideration the forces due to all operations involved in the handling and erection of the precast units. Lifting accessories may be in the form of slings/cables, hooks or shackles.
It may be necessary to equalize loads between lifting points on certain precast elements, such as beams or flat slabs. Generally, the precast unit should be erected in accordance with the tolerances provided by applicable codes, unless other tolerances are used in the design and specifications.Ī rigging system for handling and erecting precast elements requires careful and thorough preplanning. Therefore, all machines and equipment employed precast concrete element handling and erection need to be maintained to a high standard, load tested, and be suited to the intended utilization.
Safety during the handling and erection of precast concrete elements is substantially important. Finally, a trial erection operation should be considered to identify any unforeseen erection difficulties. The erection sequence shall avoid multiple handling of elements. The erection plan is commonly prepared drawings If it is important for structural stability and for access to connections at specific location. Precast concrete members shall be erected according to preplanned sequence. 9: Precast Concrete Stairs Precast Concrete Construction Considerations 1. Erection Sequence There are three arrangements of large panel system based on wall layouts which include cross-wall system, longitudinal-wall system, two-way system.įig. It consists of large walls and floor concrete panels connected in the vertical and horizontal directions.īoth horizontal and vertical panels withstand gravity loads. Large panel systems are useful for the construction of apartments and hotels. There are four major types of precast systems which are classified based on the on the load bearing structure: In order to understand the construction of precast concrete structure, different precast systems shall be known.
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