Nonstructural Partition Walls Research Articles

Effect of partition walls on the seismic response of mass-timber buildings with a post-tensioned rocking wall system

The structural-nonstructural interaction effects of nonstructural partition walls and post-tensioned CLT rocking walls in mass-timber buildings were evaluated in a parametric study. Representative 2D rocking wall units in 5-story and 12-story mass-timber archetype buildings were modeled in OpenSees. Moreover, concentrated spring models were developed to represent effective force-deformation for four different variations of partition wall detailing, and applied to the building models to represent wall densities associated with apartment and hospitality occupancies. Eigenvalue, pushover, and response-history analyses were performed on 2D models of the bare structure and those with partition wall variations. Including partition walls with fixed connection details was found to decrease story drifts and rocking wall story shears compared to the bare frame model by up to 50% in a service earthquake and up to 30% in a maximum considered earthquake. However, partition walls with deformation-compatible details were found to have negligible influence (less than 5%) on the response.

Seismic retrofit options for non-structural building partition walls: Impact on loss estimation and cost-benefit analysis

The importance of non-structural components in building performance under seismic action is well recognized in the scientific community. Damage to residential buildings registered in past earthquakes has demonstrated that the damage to non-structural components represents a substantial percentage to the resulting economic losses. In the context of performance-based earthquake engineering (PBEE), the probabilistic estimation of building-specific losses has highlighted the importance of non-structural walls, in particular, due to their direct influence on building response and contribution to the overall damage. However, limited research has been produced on the subject of seismic retrofit of non-structural components and their economic advantages. In this manuscript, focus is given to non-structural partition walls, with the aim of determining the potential economic benefit of implementing non-structural retrofit solutions, in terms of the corresponding reduction in average annual earthquake losses. Building on an extensive literature review on the state-of-the-art of non-structural retrofit solutions, representative retrofit options are investigated for six combinations of building class and seismic hazard at the building location (in Italy), by means of probabilistic seismic loss estimation and corresponding cost-benefit analysis. The results show that the seismic retrofit of non-structural partition walls only (as opposed to retrofitting both structural and non-structural components) can be sufficient to achieve a reduction of seismic losses that guarantees the return of the retrofit investment during the building’s life cycle, specifically when dealing with highly vulnerable buildings located in regions of high seismicity.

Analytical Model to Capture the In-Plane and Out-of-Plane Seismic Behavior of Nonstructural Partition Walls with Returns

AbstractThis paper presents an experimentally verified methodology to analytically model the in-plane and out-of-plane seismic behavior of steel-framed gypsum nonstructural partition walls with ret...

In-plane performance of gypsum board partition wall systems subjected to cyclic loadings

The objective of this study was to develop a better understanding of the seismic behavior of nonstructural partition walls and to provide damping methods in order to improve such behavior. This paper summarizes the findings of the study, where nine full scale wall specimens were divided into three groups of different damping systems and tested under cyclic loading conditions. The wall specimens were made of light gauge steel studs and sheathed on both sides with gypsum board (GB). Three specimens were constructed with single rubber grommet dampers, three specimens with double dampers and three wall specimens were constructed without damping system in order to have a basis for comparison. Test results included cyclic hysteresis and envelop curves of load–displacement relationships, damages and failure modes as described by photographs taken during and after testing, and ductility factor for each damping system. Based on the cyclic envelope curves, peak load capacities and their corresponding drifts were determined. Further, comparison of the peak points envelopes for none, single, and double damping specimens provided vital understanding of the relative drift capacities of the walls in addition to the ductility factor which is a measure of ductility. Damages and failure modes were noted through visual inspection and photographs. The study concluded with recommendations for further studies.

A state of the art review on the analytical simulation of ceiling, piping and partitions

It is well understood from past earthquakes and experimental studies that non-structural systems suffer more damage and sustain greater losses when compared to structural members. Also, recent years have witnessed significant progress in analytical simulation of non-structural systems. Among these non-structural systems, acoustical lay-in suspended ceilings, fire sprinkler piping and light-gauge steel-frame gypsum partition walls were paid more attention as they contributed to the major construction effort inside a building and damage losses during past earthquakes. This state-of-the-art paper aims to make a comprehensive survey on the recent modelling techniques and sketches a vision for future analytical works that can help the community better assess and improve the seismic performance of acoustical lay-in suspended ceilings, fire sprinkler piping and non-structural light-gauge steel-frame gypsum partition walls.

Evaluation of the out-of-plane behavior of stud-to-track connections in nonstructural partition walls

A series of component-level experiments have been performed aiming to characterize the out-of-plane force-displacement response and damage mechanisms of stud-to-track connections in nonstructural steel-framed partition walls. The performance of connections with various stud-to-track gap dimensions, stud and track thicknesses, and screw-attachment configurations were evaluated and compared. In addition, the accuracy of available design provisions for estimating the ultimate connection capacity was assessed. The experimental data was then used to generate capacity fragility curves in terms of displacement and force. Finally, a series of nonlinear numerical hinge models were developed and calibrated that represent the out-of-plane hysteresis behavior of stud-to-track connections.

Capacity Evaluation of Typical Track-to-Concrete Power-Actuated Fastener Connections in Nonstructural Walls

AbstractDamage to track-to-concrete connections has been widely reported in experimental studies on the seismic performance of nonstructural partition walls. These connections are commonly comprised of light-gauge cold-formed steel tracks attached to the concrete base material with power-actuated fasteners (PAFs). The failure of PAF connections resulted in a loss of strength and stiffness of the partition walls and led to subsequent damage mechanisms. A series of component-level experiments was conducted at the University of Nevada, Reno, to characterize the cyclic response and damage mechanisms of track-to-concrete PAF connections subjected to either tension or shear force. The observed damage mechanisms and force-displacement responses are presented and compared for two track thicknesses. Also, the accuracy of available design provisions for predicting the ultimate connection capacity was investigated. The data were then used to develop the capacity fragility curves in terms of connection displacement. ...

Analytical model for the in‐plane seismic performance of cold‐formed steel‐framed gypsum partition walls

SummaryThis paper proposes an experimentally verified procedure to analytically model cold‐formed steel‐framed gypsum nonstructural partition walls considering all the critical components. In this model, the nonlinear behaviors of the connections are represented by hysteretic load‐deformation springs, which have been calibrated using the component‐level experimental data. The studs and tracks are modeled adopting beam elements with their section properties accounting for nonlinear behavior. The gypsum boards are simulated by linear four‐node shell elements. The proposed procedure is implemented to generate the analytical models of three full‐scale partition wall specimens in the OpenSees platform. The specimens were tested as a part of the NEESR‐GC Project on Simulation of the Seismic Performance of Nonstructural Systems. Force‐displacement responses, cumulative dissipated energy, and damage mechanisms from the analytical simulation are compared to the experimental results. The comparison shows that the analytical model accurately predicts the trend of the response as well as the possible damage mechanisms. The procedure proposed here can be adopted in future studies by researchers and also engineers to assess the seismic performance of partition walls with various dimensions and construction details, especially where test data are not available. Copyright © 2015 John Wiley & Sons, Ltd.

Experimental Evaluation of the Raking Energy in Damping System of Steel Stud Partition Walls

Nonstructural partition walls are usually specified based on the best practice without any structural design calculations. However, given the likely severe earthquake damage to nonstructural components and the substantial cost of repair to such components, it is imperative that we develop an understanding of the seismic response of the nonstructural partition walls when subjected to earthquake loading conditions. The main objective of this investigation is to experimentally evaluate the effectiveness of utilizing low cost damping protection system in improving the seismic performance of the steel stud partition walls. Nine full scale wall specimens of 4.0 ft wide and 8.0 ft high were divided into three groups of different damping systems. Three specimens were constructed with Single Damping System (SDS), three specimens with Double Damping System (DDS) and three wall specimens with No-Damping System (NDS) in order to have a basis for comparison. Wall specimens were subjected to in-plane cyclic loadings for drifts ranging from 0.25” to 2.75” (0.3 to 3% drifts of wall height). Seismic evaluation included both ductility capacity and energy dissipation. Test results revealed that, although, damping does not influence wall capacity, it improves ductility and delays damages to later drifts. Incorporating damping system increased wind load capacity and seismic load capacity by 50 and 700% respectively. Also, ductility factors and cumulated dissipated energy increased by 40 and 112% respectively for SDS and 83 and 137% for DDS. The research study concluded that the low cost protection damping system significantly improved the seismic performance of the partition wall systems.

Seismic strengthening of masonry infilled reinforced concrete frames with steel-fibre-reinforced mortar

In addition to high seismicity, poor construction quality, incorrect detailing and structural mistakes in Turkey have caused enormous loss of life and property. Therefore, seismic rehabilitation has been a major topic for civil engineers in Turkey. The object of this research is to develop a simple method that will provide strengthening of buildings without evacuating the inhabitants. This study is based on application of steel-fibre-reinforced mortar on masonry infill walls with the aim of converting nonstructural partition walls into load-carrying walls. The specimens were one-third scale, two-storey, single-bay reinforced concrete frames with hollow brick masonry infills. The main variables were the ratio of fibre (0% and 2%), fibre reinforced mortar thickness (0, 10 and 20 mm), existence of anchorage (non-anchored or anchored) and type of fibres (steel fibre, polypropylene fibre or hybrid fibre). Strengthening by the application of steel-fibre-reinforced mortar on infill walls of frames retarded the early out of plane failure of the walls and converted the existing non-structural walls into load-carrying walls, so that the strength, stiffness and energy dissipation capacity of the frame increased significantly.

Seismic interactions between suspended ceilings and nonstructural partition walls

This study aims at observing the coupling behaviours between suspended ceilings and partition walls in terms of their global seismic performance using full-scale shake table tests. The suspended ceilings with planar dimensions of 6.0 m × 3.6 m were tested with two types of panels: acoustic lay-in and metal clip-on panels. They were further categorized as seismic-braced, seismic-unbraced, and non-seismic installations. Also, two configurations of 2.7 m high partition wall specimens, with C-shape and I-shape in the plane layouts, were tested. In total, seven ceiling-partition-coupling (CPC) specimens were tested utilizing a unidirectional seismic simulator. The test results indicate that the damage patterns of the tested CPC systems included failure of the ceiling grids, shearing-off of the wall top railing, and, most destructively, numerous partial detachments and falling of the ceiling panels. The loss of panels was mostly concentrated near the center of the tested partition wall. The testing results also confirmed that the failure mode of the non-seismic CPC systems was brittle: The whole system would collapse suddenly all at once when the magnitude of the inputs hit the capacity threshold, rather than displaying progressive damage. Overall, the seismic capacity of the unbraced and braced CPC systems could be up to 1.23 g and 2.67 g, respectively; these accelerations were both achieved at the base of the partition wall. Nonetheless, for practical applications, it is noteworthy that the three-dimensional nature of seismic excitations and the size effect of the ceiling area are parameters that exacerbate the CPC's seismic response so that their actual capacity may be dramatically decreased, leading to important losses even in moderate seismic events.

SEISMIC RESPONSE OF NON-STRUCTURAL PARTITION WALLS AND HANGING CEILING SYSTEMS

A significant amount of research has been done in order to evaluate and improve the seismic performance of the lateral load resisting system in building structures; however, there still exists a need to study the behavior of non-structural systems during an earthquake. In order to address this issue, shaking table tests were performed to look at the behavior of non-structural gypsum board partition walls typically found in steel frame structures. Both a traditional Japanese hanging ceiling system and a seismically designed hanging ceiling system were also studied. The results suggested that the non-structural partition walls undergo a rocking behavior when perpendicular walls are framed into them. In general, stiffness and damping values were large enough to affect the overall behavior of a structure. Both types of hanging ceiling systems sustained only minimal damage and performed as designed. However, the seismically designed ceiling system underwent large accelerations due to pounding with the partition walls at drift levels greater than 1/66 radians.

Nonstructural Elements in Performance-Based Seismic Design of Wood Frame Structures

This paper presents the method and analysis of a study whose objective was to numerically examine the effect that nonstructural finishes and nonstructural partition walls would have on the performance-based seismic design of a wood frame structure at the system level. The incremental dynamic analysis (IDA) approach was modified slightly, termed incremental mass analysis (IMA), and used as an investigative tool in order to determine what seismic mass numerically produces a prescribed performance level for a wood frame structure or subassembly. An illustrative example for a single wood shearwall using the IMA method that utilized an existing suite of 20 earthquakes at three different seismic hazard levels produced 60 curves. These curves for weight per unit length versus resulting transient drift from nonlinear dynamic time history analysis were analyzed using basic statistics to produce 16th, 50th, and 84th percentile IMA curves for the wood shearwalls. A one-story wood frame house was designed based on standard wood frame design concepts including windows and doors. Then, using the IMA approach presented for the wood shearwall, but with a single earthquake record, the weight at roof level versus transient drift curve was developed for three different seismic hazard levels. In order to investigate the effect of nonstructural elements numerically, analyses were performed for four versions of the wood frame structure: (1) the exterior wood shearwalls with only oriented strand board (OSB) and no finishes; (2) the exterior wood shearwalls with OSB and gypsum wall board (GWB); (3) the exterior wood shearwalls with OSB and GWB and a nonstructural partition wall; and (4) the finished structure with stucco included. Based on the analysis presented in this study, it is concluded that the allowable seismic mass can be significantly increased when non-structural elements are included in the design, in some cases more than 70 percent.

Seismic design of masonry buildings

Background material to seismic design aspects of the draft masonry design code DZ4210 is presented. The design approach is based on specified lateral force levels appropriate to the available but limited ductility, and on the principles of reinforced concrete section analyses adapted for low material strengths. Ultimate masonry strengths for compression, shear and flexure are based on the construction techniques and extent of supervision rather than on the strengths of the masonry constituents. Design lateral force coefficients for flexural strength depend on the characteristics of the structural system adopted and Structural Type factors (S) are proposed that are more appropriate to masonry structures than current values incorporated in the Loadings Code NZS4203. Shear failure is proscribed by the implementation of capacity design principles, though simplified procedures are allowed for structures with high flexural S factors. Brief discussion is made of so-called non-structural masonry, including veneers, partition, infill and secondary walls.