Seismic Rehabilitation of Existing Buildings

Steel-plate composite (SC) walls: In-plane shear behavior, database, and design

Double-skin composite (DSC) walls consist of a thick concrete infill sandwiched in between two steel faceplates on the exterior surfaces. DSC walls used in high-rise buildings have higher r...

Cyclic In-Plane Shear Behavior of Double-Skin Composite Walls in High-Rise Buildings

Finite element modeling of steel-plate concrete composite wall piers

Numerical modelling of steel-plate concrete composite shear walls

An experimental study investigated the behavior of large-scale steel-plate composite (SC) walls subjected to cyclic lateral loading. The testing program involved four rectangular SC wall specimens with an aspect ratio (height-to-length) of 1.0. The specimens were anchored to a concrete basemat with a pretensioned bolted connection that was designed to be stronger than the walls. The design parameters considered in the investigation were wall thickness, reinforcement ratio, stud spacing, and tie bar spacing. The pretest analyses, global force-displacement responses, contributions of the steel faceplates and infill concrete to the lateral resistance, load transfer between the faceplates and infill concrete, and damage to the face plates and infill, are documented. The four SC walls failed in a flexural mode characterized by tensile cracking of the concrete, tensile yielding of the steel plates, crushing of concrete at the toes of the wall, outward local buckling of the steel faceplates, and fracture...

In-Plane Seismic Behavior of Rectangular Steel-Plate Composite Wall Piers

This paper focuses on the in-plane behavior, analysis, and design of steel-plate composite (SC) wall piers without boundary elements. A series of SC wall pier specimens with aspect ratios (wall height-to-length ratios, h/lw) ranging from 0.6 to 1.0 were tested under cyclic loading until failure. The results include the lateral load-displacement (V-Δ) responses of the specimens along with observations of steel plate local buckling and concrete crushing. Detailed 3D finite element models of the SC wall specimens were developed and benchmarked using the experimental results. The models explicitly accounted for the effects of geometric nonlinearity and material inelasticity including steel local buckling, concrete crushing, and tension fracture. The benchmarked models were used to conduct parametric studies. The parameters included were the wall aspect ratio (h/lw), reinforcement ratio (ρ), and wall thickness (T). The experimental results and parametric studies indicated that the lateral load capacity...

In-Plane Behavior and Design of Rectangular SC Wall Piers without Boundary Elements

This paper presents the development and benchmarking of 3D finite element models for predicting the lateral load (in-plane shear) behavior of SC wall piers and their anchorage to the concrete basemat. The benchmarking is done using the results of selected experimental investigations (tests) from the overall database. The benchmarked models are used to conduct parametric studies, and the results from these studies are used to: (i) evaluate the lateral load-deformation of SC wall piers, and (ii) to develop recommendations for the SC wall-to-basemat anchorage design. Full-strength connection design, which requires the anchorage to be stronger than the wall pier, is recommended for the SC wall-tobasemat anchorage. A potential test matrix is recommended for further verifying the results of the numerical studies presented in this paper. INTRODUCTION AND OUTLINE Steel-concrete (SC) composite walls are being used for current safety-related nuclear facilities, and being considered for small modular reactors of the future. There are no approved US codes or standards for the design of SC walls and their connections to the concrete basemat at this time. This paper focuses on the in-plane shear behavior of SC wall piers, and proposes recommendations for anchoring them into the concrete basemat. The in-plane shear behavior of SC walls has been studied extensively in Japan, Korea, and the US. Experimental investigations have been conducted on SC wall specimens with and without flanges (or boundary elements) in Japan (Funakoshi et al. 1998) and the US (Varma et al. 2011a). In-plane shear tests have been conducted on SC wall panels with or without accident thermal loading (Ozaki et al., 2000). Takeuchi et al. (1998) have also evaluated the behavior of SC walls under axial compression, and under in-plane shear. Experimental investigations of SC wall to basemat connections have been very limited. Fujita et al. (1998) conducted tests on SC walls anchored to the concrete basemat using anchor rods or dowel bars. More recently, researchers in the US (Epackachi et al., 2013) have tested four SC wall pier specimens with different reinforcement ratios, shear stud spacing, and tie bar spacing. The tests focused on the in-plane behavior of SC wall piers, not their anchorage to the concrete basemat. This paper presents the development and benchmarking of 3D finite element models for predicting the lateral load (in-plane shear) behavior of SC wall piers and their anchorage to the concrete basemat. The benchmarking was done using the results of selected experimental investigations (tests) from the overall database including lateral loading (in-plane shear) tests of SC walls with and without flanges. The benchmarked models were used to investigate the lateral load capacity of SC wall piers without flanges. The parameters included were the wall thickness, the wall aspect (height-to-length) ratio, and steel plate reinforcement ratios. The results from the analytical parametric studies are presented along with insights into the behavior of SC wall piers. The benchmarked models were used to further investigate behavior and develop recommendations for the SC wall pier-to-concrete basemat anchorage. Full-strength connection design, which requires the 22 Conference on Structural Mechanics in Reactor Technology San Francisco, California, USA August 18-23, 2013 Division X anchorage to be stronger than the SC wall pier, is recommended based on the analysis results because it results in ductility and energy dissipation through yielding and plastification of the SC wall pier. The parametric analyses are used to recommend the relative strength ratio () of the anchorage to the SC wall pier to achieve full-strength connection design. EXPERIMENTAL STUDIES SELECTED FROM THE DATABASE This section presents relevant details of the tests that were included in the benchmarking analysis of the 3D finite element models. These included tests conducted on SC walls with flanges (Takeuchi et al. 1998) and SC walls without flanges (Epackachi et al. 2013) that were selected from the overall database mentioned earlier. SC Walls with flanges The typical configuration of specimens tested by Takeuchi et al. (1998) is shown in Figure 1(a). The bottom portion of the specimen is embedded into a concrete base slab. Another concrete loading slab is located at the top of the specimen. The specimen is subjected to cyclic lateral loading, which is applied using hydraulic actuators connected to the top loading slab. A total of seven in-plane tests were conducted on specimens with varying aspect ratios, wall thickness, and steel plate thicknesses. Three different steel reinforcement ratios, namely 1.3%, 2% and 4 % are used with wall aspect (H/L) ratios of 0.87, 1.09 and 1.53. The specimen wall length (L) was equal to 1660 mm for all the experiments. The wall thicknesses were 4.5 in., 9 in. and 13.5 in. The steel faceplate thickness was equal to 0.09 in. for all the specimens. The steel faceplates were anchored to the concrete infill using headed shear studs at equal horizontal and vertical spacing. The stud spacing was equal to 33 times of web steel plate thickness for all specimens. Figure 1. Typical configuration of test specimens (Takeuchi et. al, 1998)

SC Wall Piers and Basemat Connections: Numerical Investigation of Behavior and Design

A two-story, three-bay RC frame with code incompliant seismic design and detailing is tested using continuous pseudodynamic test method for three scale levels of Duzce ground motion. The ground motion produced minimum, signifi- cant, and severe damage states on the test structure. Diagonal cracking of the infill wall, column damage in the form of cover spalling and rebar buckling, and complete disintegration of the infill wall were the important observed damage events for the three scale levels, respectively. Nonlinear time history analyses were able to estimate the story displacement response with reasonable accuracy. The importance of element removal for near collapse damage state is unfolded. Tracing the local engineering demand parameters such as strains and curvature was found to be extremely difficult. (DOI: 10.1193/1.3609876)

Efe G. Kurt

Papers

In-Plane Seismic Behavior of Rectangular Steel-Plate Composite Wall Piers

Finite element modeling of steel-plate concrete composite wall piers

In-Plane Behavior and Design of Rectangular SC Wall Piers without Boundary Elements

SC Wall Piers and Basemat Connections: Numerical Investigation of Behavior and Design

Seismic Performance of a Deficient Reinforced Concrete Test Frame with Infill Walls