Project contacts are James Wacker at the Forest Products Laboratory, Justin Dahlberg and Brent Phares at Iowa State University
The use of cross-laminated timber (CLT) has gained popularity over the past decade, with many advances stemming from completed research and construction projects in Europe. Many inherent advantages of CLT (such as, it is prefabricated, relatively lightweight, dimensionally stable, and environmentally sustainable) have been utilized in vertical construction projects. Despite these advances, the use of CLT in bridge structures has been limited, and the adoption of CLT into governing design codes has been slow. However, CLT shows promise as a complementary or alternative construction material in bridge decks, and additional research would help characterize the structural attributes of CLT decks to guide their use in bridge projects.
This thesis focuses on the development of composite floor solutions where Cross Laminated Timber (CLT) panels are used as a base element. Preliminary investigations on shear connections between prefabricated concrete beams and CLT panels were performed. The focus is on investigations on glulam-CLT composite beam elements, and the mechanical shear connectors used to achieve composite action.
The new shear connections system evaluated in this thesis for glulam-CLT floor elements consists of double-sided punched metal plate fasteners. In order to secure the shear connection made with double-sided nail plates and to improve the shear behaviour of the joint, a combination with inclined self-tapping screws was evaluated through a shear test programme. It was found that the double-sided punched metal plate fasteners and inclined screws can effectively be combined.
The objective of this research is to develop optimum notch profile to achieve maximum connection stiffness and strength properties, characterize notched timber connection MTP-concrete floor systems, including concrete shrinkage and develop floor system details and design procedure.
This paper presents method of strengthening glued-laminated timber with aramid cords. In order to estimate the increase in load-bearing capacity, numerical analysis was carried out on three beams: unreinforced; reinforced with one layer of aramid cords...
This report presents bending tests performed on composite beams made from glulam beams and cross laminated timber (CLT) panels. The composite beam, with a T-cross section, represents a section of a floor element in a multi-storey CLT construction system. The shear connections used were made either of doublesided punched metal plate fasteners, either of inclined screws, or of a combination of both fastener types. The screws are used to secure the shear connection with double-sided nail plates with respect to possible separation forces between the glulam and the CLT. An additional test with a screw glued connection was made for comparison as the upper bound case in terms of composite action. The results show the beams with double-sided nail plates (with or without screws) achieved a very high level of composite action and an overall satisfactory behaviour. Almost full composite action was achieved for the screw-glued composite beam. A detailed design example of the beam element according to the Eurocode 5 and Finnish National Annex is presented.
The aim of the Bachelor’s thesis was to describe and evaluate the most common connection details between steel-concrete composite (SCC) beam DELTABEAM® and Cross-Laminated Timber (CLT) slab in two variations: with and without concrete topping. The purpose of the thesis was to provide a basis for future studies that are to expand the CLT range of appliance in Finland. The thesis was based on a theoretical description of the four different connectors that utilize the same working principles as the connections used for joining concrete floor slabs and the beam using the German standard details. The calculations were done according to the Eurocode 1995 and German timber design code DIN1052. The result of the thesis was the connection details library. The result of the study allows to conclude that by using described connection details, the CLT slabs and DELTABEAM® form a reliable flooring system.