EXPERIMENTS AND RELIABILITY ANALYSIS ON FRAME-TO-SHEATHING JOINTS IN LIGHT WOOD FRAMED SHEAR WALLS

To exploit the spruce-pine-fir (SPF) panel and the parallel strand bamboo (PSB) panel used in light wood framed shear wall and investigate the lateral behaviors of frame-to-sheathing joints in light wood framed shear wall with different characteristics, the experimental investigation and reliability analysis were carried out under monotonic load. The test configurations included joints with perpendicular-to-framing-grain load or parallel-to-framing-grain load, with SPF sheathing panel or PSB sheathing panel and with nail or screw. The results suggested that nailed joints with PSBpanel occurred ductile failure but other joints occurred brittle failure. Moreover, theultimate bearing capacity and the elastic stiffness of the joints under perpendicular load were higher than that ofthe joints under parallel load. The use of PSB panel and screw increased theultimate bearing capacity of the joints. Furthermore, based on Johansen yield theory and experimental results, the reliability analysis was carried out through first-order reliability methods. The results showed that the SPF-nail joints, the PSB-nail joints, and PSB-screw joints achieved the reliability requirements.

Deflections Estimation of Light Wood-framed Shear Walls Without Hold-Downs

In the structural design of light wood structures in recent years, people have paid more and more attention to estimating the lateral deformation of buildings. In order to better estimate the lateral deformation of the balsa shear wall without hold-downs, this paper carried out the lateral loading test of the wood shear wall and the monotonic loading test of the nail joint. A formula for lateral load-deformation of nail nodes suitable for engineering entities is proposed. A method for calculating the lateral deformation of wood shear walls without hold-downs is provided. The method is based on the formula for lateral deformation of light-weight timber structure shear walls in China's Code for Design of Timber Structures (GB50005–2017) [1]. This method complements the domestic wood structure regulations very well.

Updated Seismic Fragility Functions for Cold-Formed Steel Framed Shear Walls per FEMA P-58 Methodology

Performance-based earthquake engineering (PBEE) provides a robust alternative to traditional earthquake design. PBEE enables engineers to estimate expected damage, repair costs, and economic losses due to downtime for a candidate design, potentially leading to novel new designs or retrofit solutions. With the increasing application of light-frame structural systems, such as cold-formed steel (CFS) panels, in residential and commercial construction, it is necessary to develop and employ fragility functions for these systems to enable PBEE. In this regard, a set of fragility functions was previously developed by researchers based on a series of monotonic and cyclic tests for CFS framed shear walls with wood structural panel sheathing, flat strap X-bracing, and steel sheet sheathing. Recently, the senior author has led in the development of a large database of CFS framed shear wall tests, including 617 monotonic and cyclic tests conducted in the last 20 years from 25 primary sources. Based on the wider database, the fragility functions for CFS framed shear walls are re-evaluated. The developed fragility functions provide updated knowledge for application of PBEE per the FEMA P-58 methodology and are recommended for future use.

Simulation study on shear resistance of new cold-formed-steel-framed shear walls sheathed with steel sheet and gypsum boards

The objective of this article is to present finite element modelling protocols and validation studies for the new cold-formed-steel-framed shear walls sheathed with steel sheet and gypsum boards. In this model, the nonlinear behaviours of the tapping screw connectors are represented by employing the ‘Pinching4’ material along with ‘zeroLength’ elements. The constitutive relationship parameters of the ‘Pinching4’ material were determined based on experimental data from the self-tapping screw connector shear test performed by the authors. The proposed procedure is implemented to generate the analytical specimens of seven full-scale cold-formed steel shear walls in the OpenSees platform. The load–deformation relationships, hysteresis curves and skeleton curves are compared with the test results performed by the authors. The results show that the finite element models can accurately simulate the shear characteristics of the new cold-formed steel shear walls. Finally, the effects of steel sheet thickness, stud thickness, sheathed material and height-to-width ratio of walls on the shear resistance were investigated.