Fiber Reinforced Polymer as Wood Roof-to-Wall Connections to Withstand Hurricane Wind Loads

Aman Dhakal,Azadeh Parvin

doi:10.3390/civileng2030036

Abstract

Light wood roof-to-wall connections are vulnerable when subjected to high-speed winds. In lieu of traditional metal connections, the present finite element analysis (FEA) study focuses on the use of epoxy and easy-to-apply, noncorrosive FRP ties to connect the roof and the walls in wood frames. The FEA models of the wood roof-to-wall GFRP connection were validated with an experimental study in the literature. Subsequently parametric study was performed on the validated FEA models. Parameters considered were the addition of anchorages to secure the GFRP ties for FEA models of shear and uplift tests, and various FRP types. Wood roof-to-wall connection uplift model was subjected to monotonic cyclic loading to simulate the effect of wind load. In addition, carbon and basalt FRP ties were also examined under monotonic cyclic loading. To evaluate the efficiency of GFRP ties with and without anchorages, the shear and uplift design loads specified in ASCE 7-16 were calculated. Finally, a formula was proposed to approximate the shear strength of GFRP connection in comparison with double shear bolted metal plate connections. The FEA models and experimental results were in good agreement. The finite element results revealed that anchorage increased the uplift load capacity by 15% but the increase in shear capacity was insignificant. Comparing glass, carbon, and basalt FRP ties, BFRP was superior in deformation capacity and CFRP provided more stiffness on uplift test simulation. GFRP ties were found to be approximately nine times stronger in shear and two times stronger in uplift resistance than hurricane clips. Finally, the proposed formula could predict the shear strength of GFRP tie connection which in turns contributes to the design and future research.

Highlights

Most structures affected by high-speed winds and hurricanes are light wood framed residential structures
Validation of the finite element analysis (FEA) models employed for the roof-to-wall connection is presented
The finite element analysis and experimental results of an existing study on wood roof-to-wall GFRP tie connections were compared to validate the accuracy of FEA models subjected to static shear and uplift loads representing the effect of hurricane

Summary

Introduction

Most structures affected by high-speed winds and hurricanes are light wood framed residential structures. The damage caused by these extreme events may be due to many factors, such as deficient design, construction error, wall-diaphragm connection type, among others [1]. Wall-diaphragm connection can affect overall performance of any framed structure but there has been very limited test on their performance and efficiency [2]. Used traditional types of connection, like nails, bolts, and hurricane clips, have disadvantages of weakening the wood due to penetration, water seepage through the holes, rusting, and deterioration in a short period of time. Many studies are still focused on conventional nails, metal plates, and clips with nails [4,5]. Riley [5] tested two types of roof-to-wall connections: toe-nails and hurricane metal clips. Hurricane clips were found to have more residual strength and uplift capacity than toe-nailed connections. Morrison [4] rules out the use of conventional ditions of the Creative Commons Attribution

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