Developing a Large Span Timber-based Composite Floor System for Highrise Office Buildings - Phase I

Sep 15, 2026

Uploaded by Fez

The project develops a large-span timber-based composite floor system intended for 40+ story office buildings, targeting a 12 m span. It combines timber panels and timber beams into a continuous box girder concept, where panels act as flanges and beams as the web to achieve composite action through connection stiffness. Phase I evaluates six connection types using CLT, LSL, LVL, and PLVL flanges with glulam webs, measuring load capacity, stiffness, and ductility. Test and analysis support reducing screw quantity by 50% or more while maintaining high stiffness, and future work examines screw spacing, concrete topping effects, and member-to-structure connections.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages17

Reading Time43 min

AccessFree to download

EXECUTIVE SUMMARY

1 Introduction

2 Material and Methods

3 Results and Discussions

4 Conclusions

5 Future work

References

Developing a Large Span Timber-based Composite Floor System for Highrise Office Buildings Phase I by Chao (Tom) Zhang George Lee Dr. Frank Lam Prepared for Forestry Innovation Investment 1130 W Pender St, Vancouver BC V6E 4A4 Timber Engineering and Applied Mechanics (TEAM) Laboratory Department of Wood Science Faculty of Forestry University of British Columbia Vancouver, B.C., Canada April 9, 2021 EXECUTIVE SUMMARY This project proposes a timber-based composite floor that can span 12 m and be used in the construction of 40+ story office buildings. This floor system integrates timber panels and timber beams to form a continuous box girder structure. The timber panels function asthe flanges and the timber beams as the web. The beams are spaced and connected to the flange panels so that sufficient bending stiffness of a 12 m span can be achieved via the development of composite action. The current phase of this project studied the performance of the connections between timber elements in the proposed composite member. Six types of connections using different flange material and connection techniques were tested: Cross Laminated Timber (CLT), Laminated Strand Lumber (LSL), Laminated Veneer Lumber (LVL), and Post Laminated Veneer Lumber (PLVL) . Glulam was used as the web. The majority of the connections used self-tapping wood screws except one had notches. The load-carrying capacity, stiffness, and ductility of the connections were measured. The stiffness of CLT, LSL, and PLVL connections was in the same range, 19-20 kN/mm per screw. Amongst the three, LSL had the highest peak load and PLVL had the highest proportional limit. The stiffness of the two LVL screw connections was around 13 kN/mm. The notched LVL connection had significantly higher stiffness than the rest, and its peak load was in the same range as LSL, but the failure was brittle. LVL was used to manufacture the full scale timber composite floor element. With a spacing of 400 mm, the overall stiffness reached 33689 N•mm2 ×109, which was 2.5 times the combined stiffness of two Glulam beams. The predicted overall stiffness based on Gamma method was within 5% of the tested value, and the estimated degree of composite action was 68%. From both the test results and analytical modeling, the number of screws may be further reduced to 50% or less of the current amount, while maintaining a high level of stiffness. Future work includes testing the composite floor under different screw spacings, investigating the effect of concrete topping, and the connections between floor members and other structural elements. Reported by: Reviewed by: ____________________ __________________ _________________________ Chao (Tom) Zhang Research Engineer George Lee Wood Engineering Scientist Frank C.F. Lam, Ph.D., P. Eng. Professor TABLE OF CONTENT EXECUTIVE SUMMARY .............................................................................................. 2 Table of Content ................................................................................................................. 3 List of Tables ...................................................................................................................... 4 List of Figures ..................................................................................................................... 4 1 Introduction ................................................................................................................. 5 2 Material and Methods .................................................................................................. 6 3 Results and Discussions............................................................................................. 10 4 Conclusions ............................................................................................................... 15 5 Future work.....................................................

FAQs

What floor system is proposed in Phase I and what span is targeted?

Phase I proposes a timber-based composite floor system for highrise office buildings with a target span of 12 m.

How does the system achieve composite action?

Timber panels and timber beams are arranged as a continuous box girder, where panels function as flanges and beams as the web, with connections providing sufficient bending stiffness through composite action.

What connection types were tested and what key performance trends were observed?

Six connection types were tested using CLT, LSL, LVL, and PLVL flange materials with a glulam web. Stiffness for CLT, LSL, and PLVL connections was about 19–20 kN/mm per screw, LVL screw connections showed around 13 kN/mm, and the notched LVL connection had higher stiffness but brittle failure.

Sep 15, 2026

Uploaded by Fez