DOI: 10.17603/ds2-h0pj-n045
title: Database for Shear Tests on Reinforced UHPC Considering Axial Load and Fiber Alignment Effects
title: in Shear Behavior of UHPC Considering Axial Load and Fiber Alignment

description: This dataset is associated with an experimental study that investigated the effects of axial load and fiber alignment on the shear behavior of ultra-high-performance concrete (UHPC) panels reinforced with traditional steel bars at a 0.67% reinforcement ratio. Three UHPC panels were tested using the Universal Panel Tester (UPT) facility under different loading scenarios: pure shear, shear with axial compression, and shear with axial tension. Companion material tests, including compression cylinder tests, direct tension tests (DTTs), four-point bending tests (4PBs), and steel bar coupon tests, were conducted to evaluate the mechanical properties of both UHPC and reinforcing bars. The findings revealed that applying an axial tensile load ratio of 33% reduced the shear strength by 12.3%, while an axial compressive load ratio of 5% enhanced the shear strength by 77.6%. Fiber alignment analyses indicated that boundary effects induced by reinforcing bars caused a reduction in the fiber alignment factor by up to 38.1% relative to the DTT specimens. 
description: The superior mechanical properties of ultra-high-performance concrete (UHPC) allow for the design of thinner, longer-span structural elements with or without traditional reinforcing bars. This research study investigated the shear behavior of UHPC, considering the effects of axial stress fields and fiber alignment. The study encompassed laboratory tests of UHPC panels under various loading conditions using the Universal Panel Tester (UPT) facility at the University of Houston. Specifically, a set of 4-inch-thick panels with a 2.0% volumetric content of straight steel fibers was subjected to combined shear and axial loads, including both tension and compression load scenarios. Complementary to the UHPC panel tests, small-scale direct tension tests (DTTs) and large-scale tension strip tests (TSTs) were conducted to evaluate UHPC's tensile constitutive behavior and correlate findings to shear behavior. Fiber alignment analyses were performed on samples extracted from the panels and companion DTT and TST specimens to understand the influence of fiber orientation on tensile performance. Key findings indicated that axial loads significantly impact UHPC's shear strength: for example, an axial tensile load ratio of 33% can reduce the shear strength by 12.3%, whereas an axial compressive load ratio of 5% can enhance it by 77.6%. 
Additionally, fiber alignment, influenced by boundary effects induced by reinforcing bars, was found to alter the localization stress significantly. These insights suggest that UHPC's response to axial loads differs from conventional concrete, highlighting the need for tailored design considerations. The outcomes of this research provide a unique dataset aiming to optimize UHPC’s structural applications by underlining the need to understand and account for axial load and fiber alignment effects in UHPC analysis and design. The findings contribute to the development of efficient and resilient UHPC structures, benefiting the broader construction industry by informing design guidelines and promoting the adoption of UHPC in innovative structural solutions.