Flexural performance of reinforced concrete beam made with waste foundry sand as fine aggregate

PurposeThe structural behavior of reinforced concrete (RC) beams made with waste foundry sand (WFS) was examined in this study by using investigational data. Five RC beams were tested in this present work, four beams with varying WFS content and one beam with natural aggregates. The factors considered for studying the flexural performance of RC beams were WFS content (10%, 20%, 30% and 40%), 15% Ground Granulated Blast Furnace Slag (GGBS) is used as supplementary cementitious (SCM) content for all beams and tension reinforcement ratio (0.95%). The crack pattern of the RC beams with WFS (RCB1, RCB2, RCB3 and RCB4) was similar to that of referral beam–RCB0. The RC beams made with WFS (RCB1, RCB2, RCB3 and RCB4) show lesser number of cracks than referral beam–RCB0. It is observed that RCB1 beam shows higher ultimate moment carrying capacity than other RC beams. A detailed assessment of the investigational results and calculations based on IS: 456-2000 code for flexural strength exhibited that the present provisions conservatively predicts the flexural strength and crack width of RC beams with WFS and 15% GGBS. It is suggested that 10% WFS can be used to make RC beam.Design/methodology/approachIn this present work, four RC beams made WFS and one RC beam made with natural aggregates. 15% GGBS is used as SCM for all RC beams. After casting of RC beams, the specimens were cured with wetted gunny bags for 28 days. After curing, RC beams like RCB0, RCB1, RCB2, RCB3 and RCB4 were tested under a four-point loading simply supported condition. An assessment of investigational results and calculations as per IS: 456-2000 code provisions has been made for flexural strength and crack width of RC beams with WFS and 15% GGBS. The crack pattern is also studied.FindingsFrom this experimental results, it is found that 10% WFS can be used for making RC beam. The RCB1 with 10% WFS shows better flexural performance than other RC beams. RC beams made with WFS show lesser number of cracks than referral beam–RCB0. IS: 456-2000 code provisions can be safely used to predict the moment capacity and crack width of RC beams with WFS and 15% GGBS.Originality/valueBy utilization of WFS, the dumping of waste and environmental pollution can be reduced. By experimental investigation, it is suggested that 10% WFS can be used to make RC structural members for low cost housing projects.

EFFECT OF ASPECT RATIO ON THE BEHAVIOR OF GFRP-RC CIRCULAR COLUMNS UNDER SIMULATED SEISMIC LOADING

The mechanical and physical properties of glass fiber-reinforced polymer (GFRP) reinforcement are different from steel, which requires independent code provisions for GFRP-reinforced concrete (RC) members. The currently available code provisions for GFRP-RC members still need more research evidence to be inclusive. For example, the available provisions for confinement reinforcement of FRP-RC columns do not consider the effects of column aspect ratio, which is not yet supported by any available research data. In this study, two full-scale spirally reinforced GFRP-RC circular columns were constructed and tested under concurrent seismic and axial loads. Both specimens had an aspect ratio (shear span-to-diameter ratio) of 7.0, while other two specimens with an aspect ratio of 5.0, from a previous stage of this study, were included for comparison purposes. For each aspect ratio, each specimen was loaded under one of two levels of axial load; 20 or 30% of the axial load capacity of the column section. All test specimens had a 35 MPa concrete compressive strength, 350-mm diameter, 85-mm spiral pitch and 1.2% longitudinal reinforcement ratio. The experimental results were analyzed in terms of hysteretic response, drift capacity and inelastic deformability hinge length. Based on the experimental results, it can be concluded that the aspect ratio affects the magnitude of secondary moments and inelastic deformability hinge length. In addition, the aspect ratio may affect drift capacity of GFRP-RC columns, depending on axial load level.

Design Basis of Movable Scaffolding Systems Following American and European Code Provisions and Recommendations

Construction of bridges span-by-span with Movable Scaffolding Systems (MSSs) is a very efficient and competitive technology. Normally used for spans between 25 and 70m, the technology has allowed reaching longer spans due to technological advances, specifically in bridge construction equipment. Thereby, the use of MSS has become widespread and well-accepted in a large number of locations across the USA and Europe. Nevertheless, despite its extended application, there is no single specific code provision that can explain, control, and give recommendations about all aspects of MSS during its design and usage. On the contrary, the information is spread over several documents. This paper aims at bridging this gap by providing an extensive review of code provisions and recommendations that can be valid for the MSS design. Applicability of these documents is discussed by analysing loads, safety factors, load combinations, limit states, as well as structural analysis and design. After this, a proposal of a design basis for MSS is presented for each aspect mentioned following provisions and recommendations of the considered codes.