Timber-frame walls with openings: development of a method for modelling, dimensioning and construction

The project aims to develop an experimentally validated method for dimensioning shear walls with openings, allowing greater design flexibility whilst ensuring a high level of safety and cost-effectiveness.

Factsheet

Institute(s) Institute for Timber Construction IHB
Research unit(s) Earthquake Engineering
Duration (planned) 01.11.2021 - 31.07.2025
Head of project Prof. Martin Geiser
Project staff Shay Josef Assaf
Lukas Furrer
Lukas Kramer
Nadja Manser
René Steiger
Partner Bern University of Applied Sciences BFH
ETH Zurich, Institute of Structural Engineering (IBK)
Empa, Structural Engineering
Holzbau Schweiz
Swiss Timber Engineers
Ancotech AG
Keywords Timber construction, seismic safety, earthquake engineering, timber frame construction, bracing, anchorage forces, finite element modelling

Initial situation

Contemporary architecture poses a clear challenge for timber construction. Large rooms on the ground floor and expansive facade openings require robust structural bracing and careful management of horizontal forces caused by wind or seismic activity. One difficulty here is that, according to the current SIA 265 standard, sections of timber-frame walls with larger openings are to be regarded as non-load-bearing. While deviations from this standard are possible, they lack the theoretical and experimental support required for validation. Whether the areas around the openings are considered ‘load-bearing’ or ‘non-load-bearing’ significantly affects the number of anchorages and the intensity of the forces to be applied, which in turn influences the costs. The potential of timber frame shear walls with openings has already been verified at BFH-AHB as part of a preparatory project in collaboration with partners from the wood sector.

Effizienter Erdbodenschutz — In this research project, an experimentally validated method will be developed for the modelling, dimensioning and construction of shear walls with openings.

Procedure

The research project aims to develop an experimentally validated method for the modelling, dimensioning and construction of shear walls with openings. It intends to make a significant contribution to increasing the market share of Swiss buildings that use Swiss timber products, whether they are new buildings or buildings that are renovated and altered as part of preservation planning.

The project is a cooperation between BFH-AHB, Empa, ETH Zurich and two federations, Holzbau Schweiz and Swiss Timber Engineers. It is funded by the Federal Office for the Environment as part of the Wood Action Plan.

Close collaboration between research and teaching within the project enables students to participate in current developments in timber construction. As part of the project, a doctoral dissertation was completed at Empa and ETH, and several bachelor’s and master’s theses were conducted at BFH (see ‘Further information’).

Results

The tests performed and the associated numerical analyses of models show that wood-frame walls with window openings can be effectively integrated into the bracing system of buildings. This requires structural reinforcement measures that improve force transmission between the wall segments and engage the entire shear wall.

A finite-element model was developed in order to simulate the load-bearing behaviour and was validated using the test results. As a final step, the findings from the project will be compiled into a guide for practical application in structural engineering.