Torsional Strengthening of Precast L Beam using Stainless Steel Wire Mesh (SSWM) - An Experimental and Numerical Study

Abstract

Now a day’s precast concrete is a building material manufactured by pouring concrete into a reusable mould or form, curing it in a controlled environment, and then transporting this to the worksite, lifting it, and setting it in place also the productivity, quality assurance, and cost effectiveness of reinforced concrete structures are all recognised and enhanced by the use of precast concrete. Various Precast Concrete Components are available such as Beams, Columns, Shear Walls, Partition Walls etc. This indicates that precast concrete buildings are constructed of individual sections that are bolted or linked together, as opposed to cast-in-situ structures. Precast concrete constructions are most crucial feature because of the connections. The connection controls the structure's strength, stiffness, and ductility as well as the amount of forces are transferred between the precast components. Installing joints in the area where the beam and column connect always causes issues during the erection phase also the research says that this type of connections are crucial under the seismic activities. Another option for creating the beam-to-beam connection is to relocate the connection at a specific distance from the column to the beam span also in precast residential structures, beams are often L or T shaped rather than rectangular, and these beams are positioned so that they carry over the precast slabs on their flange and undergo severe torsional stress. Thus, various techniques and SSWM material for retrofitting may be employed to strengthen such precast structural elements with beam to beam connections under torsional stress. The use of Stainless Steel Wire Mesh (SSWM) in precast RC structural elements with beam to beam connections when they are only subjected to torsion has not yet been investigated.

The primary goal of this study is to assess how precast L-shaped beam to beam connections respond to torsion. In addition, if we want to discover an advanced torsional strengthening alternative, a contrast of the reaction of RC beam bolstered with SSWM are carried out also the numerical simulation is performed using finite element (FE) based software ABAQUS. There are total of Ten beams that have been prepared using M25 grade of concrete. Testing Ten RC L beams with cross sections of Flange and web as 75 mm x 75 mm and 150 mm x 225 mm and length 1300 mm is part of the investigation. The beams are made up of 5-10 mm diameter longitudinal bars and stirrups of 2 legged-8 mm diameter @ 125 mm c/c. Two different types of beam to beam connections are taken into consideration for this study out of three precast L-shaped beams and the rest are strengthened with SSWM. For RC precast beam, two distinct wet connections are taken into consideration. The different nomenclature for Precast L beams are Precast Control specimen (CS), Precast Specimen with U-shape connection (PSU), Precast Specimen with welding connection (PSW), Precast Specimen with Full Wrapping (PSU-SSWM) and (PSW-SSWM). Torque-twist response, ultimate torque and corresponding twist and damage pattern are measured.