Experimental characterization of the axial behavior of traditional masonry wall metal tie connections in cavity walls

Onur Arslan,Francesco Messali,Eleni Smyrou,İhsan E Bal,Jan G Rots

doi:10.1016/j.conbuildmat.2020.121141

Onur Arslan, Francesco Messali + Show 3 more

Open Access

https://doi.org/10.1016/j.conbuildmat.2020.121141

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Abstract

In recent years, the number of human-induced earthquakes in Groningen, a large gas field in the north of the Netherlands, has increased. The majority of the buildings are built by using unreinforced masonry (URM), most of which consists of cavity (i.e. two-leaf) walls, and were not designed to withstand earthquakes. Efforts to define, test and standardize the metal ties, which do play an important role, are valuable also from the wider construction industry point of view. The presented study exhibits findings on the behavior of the metal tie connections between the masonry leaves often used in Dutch construction practice, but also elsewhere around the world. An experimental campaign has been carried out at Delft University of Technology to provide a complete characterization of the axial behavior of traditional connections in cavity walls. A large number of variations was considered in this research: two embedment lengths, four pre-compression levels, two different tie geometries, and five different testing protocols, including monotonic and cyclic loading. The experimental results showed that the capacity of the connection was strongly influenced by the embedment length and the geometry of the tie, whereas the applied pre-compression and the loading rate did not have a significant influence.

Highlights

The number of human induced earthquakes in the province of Groningen, located in the northern part of the Netherlands, has considerably increased in the last decade
This study aims at investigating the structural response of wall ties commonly used in the traditional Dutch construction practice to connect the two masonry leaves of cavity walls, a practice used in other parts of the world
Each specimen consisted of two bricks connected by means of mortar and included an embedded metal wall tie that was designed to be representative of a portion of as-built unreinforced masonry (URM) cavity walls. 202 couplets were tested in total, consisting of two types of masonry units: solid calcium silicate (CS) and perforated clay brick masonry (CB)

Summary

Introduction

The number of human induced earthquakes in the province of Groningen, located in the northern part of the Netherlands, has considerably increased in the last decade. Most of the existing buildings in that area are composed of unreinforced masonry (URM) and were not designed to withstand earthquakes, since. The assessment of URM structures in the Groningen province has become of high relevance in earthquake engineering community. The majority of the buildings in the region are characterized by slender walls, large openings and cavity walls (i.e. double-leaf walls with an air gap in between). Buildings with double-leaf cavity walls constitute a large portion of the building stock in the Groningen gas field. A cavity wall consists of two separate parallel walls, with an inner load-bearing masonry wall and an outer veneer mostly with aesthetic and insulating functions.

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