Load-carrying Capacity Of Walls Research Articles

Effect of Chases with Renovation Techniques on the Load Carrying Capacity of Masonry Walls

Infrastructure through the masonry walls (for example, wiring and piping works) are usually installed using chases in different directions. Introducing these chases in a newly built wall will affect its overall load carrying capacity. However, there has thus far been very limited research into the effects of chases on the response and load carrying capacity of walls. This study has been undertaken to evaluate the structural behaviour of new masonry walls having chases in both horizontal and vertical directions and subjected to compression load throughout an extensive experimental programme. In addition, two renovation techniques have been proposed to infill the chases created in small scale walls (wallettes). The first technique involved the use of plastic wire mesh and cement mortar, while the second incorporated using galvanized steel channel together with the plastic wire mesh and cement mortar. Furthermore, a reference case of wallette without chases has been considered to enable reasonable comparisons to check the effect of the chases and the efficiency of the proposed renovation techniques. The outcomes of this study were used to modify the design equations proposed in the relevant codes of practice. The obtained results showed a notable reduction in the load carrying capacity of the masonry wall due to the introduction of the chases with a reduction percentage of 29% compared to the masonry wall without chase. The percentage decrease depends on the depth of the chase and the inclination angle of the load flow. The walls with horizontal chases exhibited more reduction in the load carrying capacity compared to those with vertical chases. The adopted renovation techniques using galvanized steel channel and/or plastic wire mesh with cement mortar recovered 55% and 93% of the lost load carrying capacity due to the presence of the chase and the failure was due to the de-bonded phenomena of the infill materials. Suitable factors of safety have been proposed to be incorporated in the compressive strength and modulus of elasticity formulas of the masonry walls of the BS EN codes.

Cement-Modified Backfills for Mechanically Stabilized Earth Walls with Built-In Facing

A field study was undertaken to evaluate the performance of model geotextile-reinforced mechanically stabilized earth walls constructed using locally available marginal backfill soils without and with cement modification. Cyclic plate load tests were carried out on the constructed walls both at optimum moisture content and in fully wet conditions in the case of plain backfills and in fully wet condition for cement-modified backfills. The performance and utility of the proposed built-in soil cement facing with folded-back geotextile layers were also examined. The reduction in load-carrying capacity of walls upon wetting could be compensated by cement modification of marginal backfills while maintaining the pullout resistance of reinforcing layers with nominal variation in the flexibility of walls. The performance of model walls constructed using cement-modified marginal backfills is found to be even superior to the wall constructed using free draining sand backfill in terms of higher load-carrying capacity with reduced lateral facing deformations. It was observed that the geotextile-reinforcing layers in marginal backfills also facilitate the internal drainage.