A novel procedure is proposed in this paper to investigate the capacity of parking structures to resist additional live loads that could come from many cars, potentially from heavier or driverless cars. In recent decades, the typical operating weight of passenger vehicles has risen significantly. The anticipated widespread adoption of electric vehicles (EVs), which contain heavy battery systems, may further increase live load demands. As a result, a new robust procedure is needed to assess the live load effects on parking structures. Hence, using the proposed innovative approach based on 3D influence surfaces, tributary areas (AT) and three-dimensional influence surfaces (AI) were calculated (for the first time) to examine the equivalent uniformly distributed load corresponding to selected column axial loads and beam midspan moments that are expected to be experienced during the lifetime of parking structures. As case studies, the responses of two existing multistory parking garages on the Ohio State University campus were investigated under different arrangements of two car types—standard cars and sports utility vehicles (SUVs)—and the calculated maximum live loads were compared with the current code requirements. The results show that the maximum live load for the midspan moment is conservative; however, the maximum axial column loading in the extreme scenarios presented in this paper can be larger than the specified (original) design limit of the selected parking garages. The novel methodology proposed in this paper is based on 3D influence line analysis and can be applied for any vehicle configuration and weight, and different parking arrangements or loading scenarios to investigate the performance of parking garages.

Due to light weight and extended service life, glass fiber reinforced polymer (GFRP) pipes are becoming more popular in construction industry. However, due to the lack of comprehensive structural design data, its commercial adoption is still limited. As GFRP is relatively an expensive material as compared to the conventional reinforced concrete pipes, its structural (thickness) composition can be optimized through numerical investigation. For this purpose, a GFRP pipe of 800 mm diameter, 300 mm long and 11.5 mm wall thickness was tested under parallel plate load test to investigate stiffness of the pipe. For determination of mechanical properties, specimens were prepared by hand layout technique, keeping the volume fraction ratio of glass fiber and resin same as used in actual pipe. Later, the same pipe was simulated in finite element (FE) based software ABAQUS. Mechanical properties of fiber reinforced polymer and core material determined through material characterization were utilized in FE model to define materials behavior. Numerical model was validated for pipe stiffness and failure mode with experimental result. Finally, the research was extended to study parametric analysis to investigate the effect of core strength and winding angle. Effect of winding angle was investigated for 45 MPa core strength which is also used in the actual numerical model. Optimum winding angle of 60o was observed through parametric study. After, effect of core strength was investigated for 60o winding angle keeping all other variables constant. It was observed that load carrying capacity of GFRP pipe increased with the increasing core strength.

The increasing demand for sustainable concrete has encouraged the utilization of waste materials. This study investigates the combined effect of household waste ash (HWA) as a partial replacement of fine aggregate (0 to 20%) and silica fume (SF) as a cement replacement (10%). The mechanical, physical, and microstructural properties of concrete were evaluated after exposure to 250 °C for 220 minutes. Concrete workability, density, water absorption, compressive strength, splitting tensile strength, ultrasonic pulse velocity (UPV), SEM and EDX analysis were used to determine the influence of HWA. The results indicate that HWA reduced the concrete workability due to the physical properties of HWA (porous and rough texture). However, all mixes maintained acceptable workability (slump greater than 50 mm). Mechanical performance improved at optimum replacement levels. The 10% HWA increased compressive strength from 39.4 MPa to 42.5 MPa (7.8%). The maximum splitting tensile strength of 3.81 MPa (7.6% increase) was achieved at 15% HWA. SEM analysis indicates that 10-15% HWA enhanced mix densification and improved the interfacial transition zone (ITZ) through filler effects. However, excessive replacement (20% HWA) resulted in a less compact microstructure. The findings conclude that 10 to 15% HWA provides an optimum balance and produces concrete with adequate mechanical strength, a refined microstructure, and acceptable thermal stability after exposure to 250 °C.

The alkali–silica reaction (ASR) poses a serious threat to the durability and structural integrity of concrete infrastructure worldwide. This study critically evaluates the effectiveness of ASTM C227 and ASTM C1260 standards in determining the ASR potential of five locally sourced aggregate samples, including Kuchlack, Jabal-e-Noor, Hanna, Speyzaind, and Bolan. Physical and chemical characterization, alongside petrographic analysis, were conducted to identify reactive components within the aggregates. Mortar bar expansion tests were performed under both ASTM protocols to assess elongation and determine reactivity. The findings strongly affirm that ASTM C1260 is more effective than ASTM C227 in identifying potentially deleterious aggregates. While all samples remained within acceptable expansion limits under ASTM C227, the Sepyzaind aggregate demonstrated excessive expansion under ASTM C1260, confirming its slow-reactive nature. This was further verified by a marked reduction in compressive strength (16 %) and modulus of rupture (9.3 %) for Sepyzaind aggregate under ASTM C1260 conditions. The remaining four aggregates consistently tested non-reactive across all parameters. These results emphasize the superior diagnostic capability of ASTM C1260 and underscore the necessity for rigorous ASR evaluation, especially in regions that depend on local aggregate sources. This study offers critical insights for engineers, researchers, and policymakers committed to enhancing the long-term performance and safety of concrete structures.

In this study, an AI model for predicting the concentration of heavy metal (HM) present in the agricultural waste ashes (AWAs) such as sugarcane bagasse ash (SCBA) and rice husk ash (RHA) is developed from the physio-chemical properties of the ashes. Thirty-two (32) samples of SCBA and RHA were collected and characterized through detailed analysis by Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), scanning electron microscope (SEM), X-ray diffraction analysis (XRD), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), Energy dispersive X-ray (EDX) and atomic absorption spectroscopy (AAS). The study results indicate that AWAs are rich in HMs that can be categorized by loss on ignition, and have great potential as sustainable construction materials. The machine learning model built with deep neural networks has high prediction accuracy ( R ² = 0.99) for HMs concentrations, which proves the model’ effectiveness. This research can be used to encourage the introduction of AWAs in the construction industry, which would result in a reduction of environmental hazards. Hence, current work aims to open new horizon for researchers to use chemical characterization for utilization of waste ashes for manufacturing of construction materials.

Pre-casting of girders, columns, roof elements and wall panels is a common practice but to precast the gigantic concrete bridge transoms is a novel idea for a developing country like Pakistan. Its high cost and laborious techniques of fabrication and hoisting restrict its use in the construction industry. This case study discusses the bus rapid transit system (BRTS) project in the city of Lahore, Pakistan, where precast transoms were installed for the first time due to traffic congestion and the strict timeline of this mega project. This paper describes various processes involved in the fabrication of precast transoms at the yard and during their launching at the job site. Furthermore, a comparison has been drawn between precast and cast-in-situ construction of transoms for designers and implementing engineers to help them in adopting a suitable and economical construction technique, keeping in view the timelines, cost and objectives of the project. Precast transoms help complete work quickly with good quality, but they are economical only when properly planned and done on a large scale, especially at congested sites where traffic closure time is limited. Overall, precast transoms are 36 % costlier than their cast-in-situ counterparts. For normal small projects with no time pressure, cast-in-situ transoms are a better and more economical option as they require only common skills and routine equipment.