![]() ![]() As a result, the minimum lap and development lengths can vary considerably from one code to the next as well as from one design method to another. In addition, these detailing requirements have been frequently revised in recent years. The required length of lap or development is determined according to the design procedure used (allowable stress design or strength design). Reinforcing bars may be spliced by lapping the reinforcement, by proprietary mechanical splices or by welding. The development of the reinforcing bars relies on mechanical interlock of the bar deformations, hook, and/or anchor along with sufficient masonry cover to prevent splitting of the masonry. Reinforcement can be developed by embedment length, hook, or mechanical anchoring device. Splicing of reinforcement serves a similar purpose: to adequately transfer stresses from one reinforcing bar to another. Minimum development lengths are necessary to adequately transfer stresses between reinforcement and the grout or mortar in which it is embedded. 7), covers these requirements based on the 20 editions of the IBC. TEK 12-6, Splices, Development and Standard Hooks for Concrete Masonry (ref. In addition, prestressing steel is discussed in Post-Tensioned Concrete Masonry Wall Construction, TEK 3-14 (ref. 5) includes basic material requirements, corrosion protection and placement tolerances for reinforcement used in concrete masonry construction. the 2011 MSJC includes new lap splice length provisions for when confinement reinforcement is used at lap splices.under 2011 MSJC allowable stress design, the allowable tensile stress, F s, of Grade 60 steel was increased from 24,000 psi (166 MPa) to 32,000 psi (221 MPa), and.There are two main differences between the 20 editions of the MSJC that impact reinforcement development and splice lengths in the corresponding 20 editions of the IBC: Differences between the MSJC and IBC are noted in the text when they occur. ![]() Masonry design in these codes is primarily based on Building Code Requirements for Masonry Structures (MSJC) (refs. This TEK presents these requirements, based on the provisions of both the 20 editions of the International Building Code (IBC) (refs. ![]() The minimum lap length for compression bars must be 12inches.Building codes include requirements for minimum reinforcement development lengths and splice lengths, as well as requirements for standard hooks, to ensure the adequate transfer of stresses between the reinforcement and the masonry. The lap length for compression lap splice is calculated as per ACI 12.16.1 as Where, ld= development length, which is calculated as per ACI 12.2 ( Without taking into consideration the modification factor).The minimum lap length is 12 inches 3. As per ACI 318, the tension lap splices are classified into two classes Class A and Class B ( Table R12.5.2, ACI 318) for which the lap length are as follows: Hence, the lap splice, in this case, shows varied interaction depending on the concrete strength, grade of steel reinforcement, location, bar size ,and spacing. This hence results in a continuous line of reinforcement. In a tension lap, the force is transferred from the reinforcement bars to the concrete by the bond which in turn force back to the reinforcement. The lap splice length in tension reinforcement is calculated as per ACI 12.15. Also Read: Methods of Splicing Reinforcement Bars 2.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |