Construction Technologies and Architecture Vol. 15

Abstract: The construction of resilient infrastructure and buildings is a key requirement for sustainable cities and communities. Tsunami is a natural hazard that can have a devastating impact on coastal communities. The 2010 Chile and 2011 Great East Japan tsunamis changed the way that structural engineers estimate design loads for structures. During these events, coastal protective structures and waterfront concrete buildings failed to sustain the tsunami hydrodynamic forces. This paper demonstrates the performance evaluation of a numerically simulated case-study tall building located at the Karachi coastal belt employing the ASCE 7-16 provisions. Results include the resilient-based assessment of the overall building and individual component performance when subjected to hydrodynamic loadings and debris damming effects due to active-sea debris such as wooden logs and shipping containers.

Abstract: Civil infrastructure is prone to deterioration due to several factors like loading and environmental agents. Condition assessment of these infrastructures is done on a visualization basis by the field inspector. The data collected by the inspector is biased and depends on the perception, experience, and visuals of the inspector. The data collected in terms of images and characteristics of the deterioration is recorded on a qualitative basis in the data log. The report is then presented to the managers or decision-makers to make decisions on the maintenance of the facility. In this era, various sensing and visualization technologies are available that can be utilized to create a digitized as-built model in 3D with exact dimensions and deteriorations, also known as a 3D re-constructed model. In this research, a 3D reconstructed model of an elevated overhead water tank has been created using laser scanning, UAV (Unmanned aerial vehicle). Artificial intelligence has been used to detect and measure cracks or openings on the surface of the structure. Deflection and rotation of the elements of the structure have been quantified by superimposing the point cloud model over the as-planned model in the interface of Navisworks.

Abstract: Infrastructure development serves as an indicator of a country’s social and economic growth. Bridges are the key assets of infrastructure projects that are built for a design life of more than 50 years. During their lifespan, they are subjected to defects and deterioration due to physical changes, chemical attacks, internal reactions, etc. that are required to be addressed by timely inspection and monitoring. Inspection practices have a great impact on maintenance planning and decision-making. Since bridges are public infrastructure the budget allocated to their repair and maintenance is limited. Therefore, there arises a need for accurate, measurable, reliable, and cost-effective technologies for bridge health monitoring that can be incorporated into decision-making tools to prioritize repair and maintenance strategies. In recent years the trend has shifted from visual inspection to IoT-based condition assessment. This technique evaluates the bridge’s global and localized, and static and dynamic responses. However, there is a need to develop a systematic structure for a bridge health monitoring system, standardizing the data acquisition, processing, and transmission from a group of sensors to evaluate the existing condition of the bridge. This study proposes a conceptual IoT-based framework for structural health monitoring of existing reinforced concrete bridges for informed decision-making along with development of data acquisition system.

Abstract: In today's contemporary world, concrete is a top choice, but curing issues persist due to water scarcity. Civil engineering offers alternatives like polyethylene and self-curing concrete, but they are costly. Over the past two decades, wastewater recycling for purposes like concrete curing has gained attention after treatment. The aim of this literature review is to thoroughly assess the viability of using treated wastewater, particularly sewage water, for the curing process. It focuses on articles from reputable journals published over the last decade. The review begins by examining concrete curing and its techniques and insufficiency cause. Subsequently, it delves into the philosophy of wastewater treatment need, source and the treatment process itself. Consequently, waste water treatment is suggested as an affordable and eco-friendly solution for concrete curing. Lastly, the feasibility of adopting treated waste water in developing nations is scrutinized, with an emphasis on its real-world applicability following comprehensive analysis of its overall performance. Membrane filtration technique is preferred for treatment of waste water due to its reasonable results.

Abstract: Wind energy has been making its way into renewable energies until today, experiencing a continuous growth worlwide that leads to the urgent task of reflecting on and solving the issue of the recycling of the wind turbine blades. Their complex composition causes that currently there is no a widely acepted solution for it. This study evaluates the incorporation of waste from the crushing of wind turbine blades, which contains fibers, into self-compacting concrete, which can be used for producing any construction element. Therefore, five concrete mixes were made with different percentages of this waste, including a reference mix without this waste. The addition of waste increased the content of fibers in the concrete, which in turn implied an increase in the water/cement ratio. This situation led to a worsening of the mechanical performance of concrete as the waste amount increased, although it was partially compensated by the stitching effect of the fibers. The concrete mix with 1.5% in volume of this waste exhibited flexural and compressive strengths very similar to those of the reference concrete. This shows that incorporating the waste from the crushing of wind turbine blades can allow to produce structural self-compacting concrete.

Abstract: Tall buildings require slender shear walls as fundamental structural elements since the structure’s performance and safety depend on the walls' capacity to bear lateral loads while retaining their ductility. Concrete that has short fibers, like those made of steel or glass is known as fiber concrete. By increasing the ductility of concrete, these fibers can increase its resistance to brittle shear failure. This work aimed to investigate the effects of fiber concrete on thin shear wall ductility. The ductility of fiber concrete shear walls is significantly higher than that of typical concrete shear walls, according to tests conducted on thin shear walls made of both types of concrete. This occurred because of the fibers in the fiber concrete filling up the cracks and stopping them from getting worse. It has been stated that fiber concrete can be utilized as a building material in a variety of ways after being treated. Its application to cylinder shear walls has not been documented solely, though. Therefore, a thorough assessment of the literature regarding the potential of steel fiber concrete for the prevention of shear cracks. The optimal choice for fiber concrete in this application is characterized by a high fiber aspect ratio and a minimum fiber volume fraction of 1%, with steel fiber concrete being highly recommended. The study's findings imply that slender shear walls' ductility can be increased and their resistance to brittle shear failure increased by using steel fiber concrete.

Abstract: The construction industry significantly contributes to global CO₂ emissions and environmental impact, mainly due to concrete usage, which consumes vast resources and energy while emitting CO₂. Researchers are exploring alternatives such as geopolymer concrete (GPC), formed without traditional cement but through alkaline activation of industrial by-products like fly ash, ground granulated blast furnace slag, bentonite, and metakaolin clay. This study evaluates the effects of incorporating bentonite and polypropylene (PP) fibers on the workability and strength properties of GPC based on slag. Bentonite substituted 10% of slag, and PP fibers were added at varying ratios (0.5%, 0.75%, and 1%). Both untreated and heat-treated bentonite, heated up to 200°C, were used. Workability was assessed using a slump cone, while mechanical properties, including compressive, split-tensile, and flexural strength, were analyzed. Notably, heat-treated bentonite and PP fibers exhibited significant enhancement in the mechanical properties of the GPC mixes.

Abstract: The utilization of Fiber Reinforced Concrete (FRC) as a structural material is steadily on the rise. Conventional concrete is characterized by its brittleness, displaying a flexural strength that falls within the range of 10-15% of its compressive strength. Incorporation of fibers into concrete enhances various mechanical properties, including tensile strength, flexural strength, and ductility. An advantageous feature of FRC is its capacity to consider cracked concrete below the neutral axis in the cross-section of a beam to some extent. Important factors influencing the flexural strengths of both Plain Concrete (PC) and FRC include the modulus of rupture, corresponding deflection, toughness index, energy absorption, and density. This results in a diminished requirement for additional reinforcement in beams. The modified stress-strain diagram proposed by Bashara proves valuable in integrating the effect of FRC on the tension side, an aspect previously neglected due to the inherent weakness of PC in tension. The ongoing literature review seeks to comprehensively explore the potential of fiber-reinforced concrete in beams situated below the neutral axis, concentrating on articles published in highly reputable journals over the past decade.

Abstract: Fiber Reinforced Polymer (FRP) has been used in construction as it is lightweight, has flexural strength, is more durable and resistant to corrosion, impact, and fire. Finite Element Analysis (FEA) is a modern technique to predict the tensile behavior and cracking pattern of structural members using nonlinear finite element analysis (NLFEA). In this current study, 11 specimens of Glass Fiber Reinforced Polymer (GFRP) reinforced concrete (RC) Beams with different reinforcement bars (#5, #6 and #8 bars) and spacing (30mm, 38mm and 50 mm) along with two different concrete strengths (Normal and high strength) were modelled to predict the flexural behavior, Moment deflection behavior and cracking pattern using ABAQUS 6.12. These specimens were modeled in ABAQUS using CDP Model and calibration was performed on basis of viscosity, dilation angle and meshing size. The outcomes of numerical modeling were compared with those of the experimental results. It has been shown that there is a slight disparity with very small differences between the experimental and numerical results.