Timber and wood-based engineered products are important as structural materials, especially in th... more Timber and wood-based engineered products are important as structural materials, especially in the drive towards sustainable technologies and construction. It is very important to improve the properties of these products, making them more competitive and reliable. This applies particularly to larger, more complicated structures where timber is becoming a realistic alternative to other construction materials.
The orthotropic properties of timber are well known - strong and stable along the grain, weak and susceptible to movement across the grain. Combining wood with other materials, to achieve composite action, enables the strength of wood to be realized and its shortcomings to be strengthened or eliminated.
COST Action FP1004, “Enhance mechanical properties of timber, engineered wood products and timber structures” provides a network for learning and development in a range of connected topics. This conference will present and record various methods for improving wood with other materials. It brings researchers and practitioners together to learn about various applications, and enables them to take part in discussions about future research and development.
The purpose of the COST program is to strengthen Europe and other countries in scientific and technological research, for peaceful purposes, through the support of cooperation and interaction between European researchers. This conference adheres to these principles. It will be an extraordinary opportunity to hear presentations from highly specialist, invited speakers and to participate in debate, in the island of Cyprus, which is located at the crossroads of three continents Europe, Asia and Africa in the Northern-east part of the Mediterranean Sea.
The versatility of the construction systems for prefabricated houses with timber frame constructi... more The versatility of the construction systems for prefabricated houses with timber frame construction and the interaction of components are important sources of difficulties for analytical determination of their response to seismic excitation. The solving of the problem of reliable prediction of structural behaviour response to earthquake excitation can be approached by the experimentally based development of inelastic computational model. The inelastic spring element for DRAIN-2DX was developed at the University of Ljubljana and named as “ULS” element (Universal Longitudinal Spring). Inelastic behaviour is determined by universal hysteretic rules. ULS element is capable to simulate the behaviour of all kinds of connectors or supports, which responses are in inelastic range. The paper describes the approach to modelling wood frame structure with DRAIN-2DX and CANNY-E programs where ULS was applied.
This paper deals with the issue of seismic strengthening of existing older reinforced concrete fr... more This paper deals with the issue of seismic strengthening of existing older reinforced concrete frame buildings. A new method of strengthening by applying a new outer shell made of cross laminated timber (crosslam or Xlam) plates is presented. A seismic strengthening case study is presented on a 3 story reinforced concrete frame building. The results of quasi-static cyclic unreinforced masonry wall tests and shaking table tests of a (strengthened) two-story reinforced concrete frame with and without infill are presented.
Cross laminated timber (CLT, X-lam) started its mass production in the beginning of the 21st cent... more Cross laminated timber (CLT, X-lam) started its mass production in the beginning of the 21st century. Over time it has become one of the most used products in the timber construction industry with its worldwide use constantly growing. The quantity of yearly cut timber especially in Europe is slowly reaching its maximum and its price is rising. Hence conventional CLT is becoming more expensive and less competitive on the market on the one hand and more straining on the forest on the other hand. CLT technology has still lots of potential for improvement that would allow for more effective and economic use under different boundary conditions. This paper presents a new type of cross-laminated timber plates called the "Xlam ribbed plates" (XR-lam). The main objective of the newly proposed plates is to optimise the structural performance of regular CLT in terms of material use by incorporating ribs into the main panel structure as well as simplifying their production. Analyses s...
Light prefabricated timber elements and structures become increasingly popular in the European bu... more Light prefabricated timber elements and structures become increasingly popular in the European building market. Especially multi-storey timber struc-tures up to five storeys are in trend, now. Hereby profound attention has to be paid to buildings located in earthquake prone areas of Middle and South Europe. Appropriate guidelines for the design have to be set to assure sufficient seismic resistance. It is obvious in this context that there is a need for development of an European standard covering cyclic testing of construction parts and wall dia-phragm segments. The new standard should also include the criteria for determi-nation of the limitations of inter-story drifts according to the concept of per-formance based earthquake engineering design. In the paper presented the importance of experimental investigations re-lated to the earthquake response of anchored horizontally loaded wall dia-phragms for earthquake safe design of light prefabricated timber buildings is addressed. Cycl...
Investigations on in-plane loaded wooden wall elements are part of a com-prehensive research prog... more Investigations on in-plane loaded wooden wall elements are part of a com-prehensive research program performed in recent years at University of Ljubl-jana to enable better understanding of response of wooden buildings exposed to earthquake action. Recently, Division of Timber Construction of MPA Univer-sity of Stuttgart joined the research program. This paper reports on some results emerging from the research cooperation. Eurocode 5 contains two methods for determination of the racking strength of cantilever-type wall diaphragms: an analytical approach and an experimental approach using the test protocol according to EN 594. Both approaches are re-lated only to timber frame walls having sheathing plates. The test procedure ac-cording to EN 594 predefines the partially anchored wall which does not neces-sarily represent the actual anchorage and loading conditions in the building and does not apply for cyclic horizontal loads to simulate earthquake loadings. It is reported on experime...
This paper presents the development of two new types of hybrid cross-laminated timber plates (HCL... more This paper presents the development of two new types of hybrid cross-laminated timber plates (HCLTP) with an aim to improve structural performance of existing cross-laminated timber plates (Xlam or CLT). The first type are Xlam plates with glued timber ribs and the second type are Xlam plates with a concrete topping. A numerical optimisation was performed to study optimal plate setups in terms of ultimate limit state and serviceability limit state requirements. The numerical outcomes served as input for defining the specimens for experimental tests on subassemblies and full-scale specimens. The new elements in general show improved structural performance with less material used. Experimental and numerical investigations serve as essential information for further extensive parametric studies of hybrid cross-laminated timer plates and development of design models and principles for implementation in the building codes.
Light prefabricated timber elements and structures become increasingly popular in the European bu... more Light prefabricated timber elements and structures become increasingly popular in the European building market. Especially multi-storey timber structures up to five storeys are in trend, now. Hereby profound attention has to be paid to buildings located in earthquake prone areas of Middle and South Europe. Appropriate guidelines for the design have to be set to assure sufficient seismic resistance. It is obvious in this context that there is a need for development of an European standard covering cyclic testing of construction parts and wall diaphragm segments. The new standard should also include the criteria for determination of the limitations of inter-story drifts according to the concept of performance based earthquake engineering design.
This paper deals with an important theme about possibilities of upgrading existing buildings with... more This paper deals with an important theme about possibilities of upgrading existing buildings with additional stories made of light prefabricated systems. The purpose of the study was to analyse the seismic response of an existing three-storey reinforced concrete building upgraded with three different construction systems: 1) rigid box of cross laminated (Xlam) timber panels, 2) braced steel frame with RC slabs, and 3) combined steel frame with Xlam timber wall infills and floor diaphragms. Modal analysis and linear dynamic analysis were performed for the combined existing and upgrade structures of all three types using the exact modelling and two simplified models in order to study the possibility of simplification of the earthquake analysis and different impacts of the upgrade structures on the existing building. The analyses show the major differences between the simplified models in comparison to the realistic one. Comparisons of different properties and possible problems have be...
Cross-laminated timber has recently gained great popularity in earthquake-prone areas for constru... more Cross-laminated timber has recently gained great popularity in earthquake-prone areas for construction of residential, administrative, and other types of buildings. At the Laboratory of the Institute of Earthquake Engineering and Engineering Seismology in Skopje, comparative full-scale shaking-table tests of cross-laminated timber panel systems have been carried out as a part of the full research program on the seismic behavior of these types of wooden systems, realized by Institute of Earthquake Engineering and Engineering Seismology, Skopje, and the Faculty of Civil and Geodetic Engineering (UL FCG), University of Ljubljana. Two different specimens built of cross-laminated timber panels have been tested: specimen containing a pair of single-unit principal wall elements (Specimen 1) and specimen containing a pair of two-unit principal wall elements (Specimen 2). In this article, the results from the shaking-table tests obtained for Specimen 2 and numerically verified by using appro...
AbstractThis paper investigates the seismic analysis of multistory cross-laminated timber (XLAM) ... more AbstractThis paper investigates the seismic analysis of multistory cross-laminated timber (XLAM) buildings. The influence of different parameters such as wall geometry, vertical load level, friction, and, most importantly, connection stiffness, strength, and ductility is assessed. Linear and nonlinear finite-element (FE) analyses are carried out on a hypothetical 4-story case study building. The actual load-carrying capacity of the case study building is calculated with the nonlinear static pushover method and assessed using displacement-based design. The XLAM building behavior factors are then derived for different cases using a simplified method. Values in the range 2–3 have been obtained depending on whether monolithic or segmental walls (namely made of approximately 2-m-wide panels screwed to the adjacent ones) are used. Further nonlinear dynamic analyses carried out on a part of the case study building show that friction may have a beneficial effect on the seismic resistance of XLAM buildings. Howeve...
The paper investigates the influence of modelling different types of connections in multi-storey ... more The paper investigates the influence of modelling different types of connections in multi-storey cross-laminated ('crosslam') buildings when performing different types of analyses. More specifically, linear modal response spectrum analysis, nonlinear static (pushover) analysis assessed with a modified N2 method, and nonlinear time-history analysis are considered herein. In the research done by other authors, so far only the behaviour of certain types of crosslam building assemblies was investigated. In this paper it is shown how different connection details influence the building's global ductility and peak ground acceleration. Basic values of overstrength factors for BMF 105 angular brackets and 8 mm self-tapping screws are also presented and the importance of using the overstrength concept in design is demonstrated on a case-study wall.
Timber and wood-based engineered products are important as structural materials, especially in th... more Timber and wood-based engineered products are important as structural materials, especially in the drive towards sustainable technologies and construction. It is very important to improve the properties of these products, making them more competitive and reliable. This applies particularly to larger, more complicated structures where timber is becoming a realistic alternative to other construction materials.
The orthotropic properties of timber are well known - strong and stable along the grain, weak and susceptible to movement across the grain. Combining wood with other materials, to achieve composite action, enables the strength of wood to be realized and its shortcomings to be strengthened or eliminated.
COST Action FP1004, “Enhance mechanical properties of timber, engineered wood products and timber structures” provides a network for learning and development in a range of connected topics. This conference will present and record various methods for improving wood with other materials. It brings researchers and practitioners together to learn about various applications, and enables them to take part in discussions about future research and development.
The purpose of the COST program is to strengthen Europe and other countries in scientific and technological research, for peaceful purposes, through the support of cooperation and interaction between European researchers. This conference adheres to these principles. It will be an extraordinary opportunity to hear presentations from highly specialist, invited speakers and to participate in debate, in the island of Cyprus, which is located at the crossroads of three continents Europe, Asia and Africa in the Northern-east part of the Mediterranean Sea.
The versatility of the construction systems for prefabricated houses with timber frame constructi... more The versatility of the construction systems for prefabricated houses with timber frame construction and the interaction of components are important sources of difficulties for analytical determination of their response to seismic excitation. The solving of the problem of reliable prediction of structural behaviour response to earthquake excitation can be approached by the experimentally based development of inelastic computational model. The inelastic spring element for DRAIN-2DX was developed at the University of Ljubljana and named as “ULS” element (Universal Longitudinal Spring). Inelastic behaviour is determined by universal hysteretic rules. ULS element is capable to simulate the behaviour of all kinds of connectors or supports, which responses are in inelastic range. The paper describes the approach to modelling wood frame structure with DRAIN-2DX and CANNY-E programs where ULS was applied.
This paper deals with the issue of seismic strengthening of existing older reinforced concrete fr... more This paper deals with the issue of seismic strengthening of existing older reinforced concrete frame buildings. A new method of strengthening by applying a new outer shell made of cross laminated timber (crosslam or Xlam) plates is presented. A seismic strengthening case study is presented on a 3 story reinforced concrete frame building. The results of quasi-static cyclic unreinforced masonry wall tests and shaking table tests of a (strengthened) two-story reinforced concrete frame with and without infill are presented.
Cross laminated timber (CLT, X-lam) started its mass production in the beginning of the 21st cent... more Cross laminated timber (CLT, X-lam) started its mass production in the beginning of the 21st century. Over time it has become one of the most used products in the timber construction industry with its worldwide use constantly growing. The quantity of yearly cut timber especially in Europe is slowly reaching its maximum and its price is rising. Hence conventional CLT is becoming more expensive and less competitive on the market on the one hand and more straining on the forest on the other hand. CLT technology has still lots of potential for improvement that would allow for more effective and economic use under different boundary conditions. This paper presents a new type of cross-laminated timber plates called the "Xlam ribbed plates" (XR-lam). The main objective of the newly proposed plates is to optimise the structural performance of regular CLT in terms of material use by incorporating ribs into the main panel structure as well as simplifying their production. Analyses s...
Light prefabricated timber elements and structures become increasingly popular in the European bu... more Light prefabricated timber elements and structures become increasingly popular in the European building market. Especially multi-storey timber struc-tures up to five storeys are in trend, now. Hereby profound attention has to be paid to buildings located in earthquake prone areas of Middle and South Europe. Appropriate guidelines for the design have to be set to assure sufficient seismic resistance. It is obvious in this context that there is a need for development of an European standard covering cyclic testing of construction parts and wall dia-phragm segments. The new standard should also include the criteria for determi-nation of the limitations of inter-story drifts according to the concept of per-formance based earthquake engineering design. In the paper presented the importance of experimental investigations re-lated to the earthquake response of anchored horizontally loaded wall dia-phragms for earthquake safe design of light prefabricated timber buildings is addressed. Cycl...
Investigations on in-plane loaded wooden wall elements are part of a com-prehensive research prog... more Investigations on in-plane loaded wooden wall elements are part of a com-prehensive research program performed in recent years at University of Ljubl-jana to enable better understanding of response of wooden buildings exposed to earthquake action. Recently, Division of Timber Construction of MPA Univer-sity of Stuttgart joined the research program. This paper reports on some results emerging from the research cooperation. Eurocode 5 contains two methods for determination of the racking strength of cantilever-type wall diaphragms: an analytical approach and an experimental approach using the test protocol according to EN 594. Both approaches are re-lated only to timber frame walls having sheathing plates. The test procedure ac-cording to EN 594 predefines the partially anchored wall which does not neces-sarily represent the actual anchorage and loading conditions in the building and does not apply for cyclic horizontal loads to simulate earthquake loadings. It is reported on experime...
This paper presents the development of two new types of hybrid cross-laminated timber plates (HCL... more This paper presents the development of two new types of hybrid cross-laminated timber plates (HCLTP) with an aim to improve structural performance of existing cross-laminated timber plates (Xlam or CLT). The first type are Xlam plates with glued timber ribs and the second type are Xlam plates with a concrete topping. A numerical optimisation was performed to study optimal plate setups in terms of ultimate limit state and serviceability limit state requirements. The numerical outcomes served as input for defining the specimens for experimental tests on subassemblies and full-scale specimens. The new elements in general show improved structural performance with less material used. Experimental and numerical investigations serve as essential information for further extensive parametric studies of hybrid cross-laminated timer plates and development of design models and principles for implementation in the building codes.
Light prefabricated timber elements and structures become increasingly popular in the European bu... more Light prefabricated timber elements and structures become increasingly popular in the European building market. Especially multi-storey timber structures up to five storeys are in trend, now. Hereby profound attention has to be paid to buildings located in earthquake prone areas of Middle and South Europe. Appropriate guidelines for the design have to be set to assure sufficient seismic resistance. It is obvious in this context that there is a need for development of an European standard covering cyclic testing of construction parts and wall diaphragm segments. The new standard should also include the criteria for determination of the limitations of inter-story drifts according to the concept of performance based earthquake engineering design.
This paper deals with an important theme about possibilities of upgrading existing buildings with... more This paper deals with an important theme about possibilities of upgrading existing buildings with additional stories made of light prefabricated systems. The purpose of the study was to analyse the seismic response of an existing three-storey reinforced concrete building upgraded with three different construction systems: 1) rigid box of cross laminated (Xlam) timber panels, 2) braced steel frame with RC slabs, and 3) combined steel frame with Xlam timber wall infills and floor diaphragms. Modal analysis and linear dynamic analysis were performed for the combined existing and upgrade structures of all three types using the exact modelling and two simplified models in order to study the possibility of simplification of the earthquake analysis and different impacts of the upgrade structures on the existing building. The analyses show the major differences between the simplified models in comparison to the realistic one. Comparisons of different properties and possible problems have be...
Cross-laminated timber has recently gained great popularity in earthquake-prone areas for constru... more Cross-laminated timber has recently gained great popularity in earthquake-prone areas for construction of residential, administrative, and other types of buildings. At the Laboratory of the Institute of Earthquake Engineering and Engineering Seismology in Skopje, comparative full-scale shaking-table tests of cross-laminated timber panel systems have been carried out as a part of the full research program on the seismic behavior of these types of wooden systems, realized by Institute of Earthquake Engineering and Engineering Seismology, Skopje, and the Faculty of Civil and Geodetic Engineering (UL FCG), University of Ljubljana. Two different specimens built of cross-laminated timber panels have been tested: specimen containing a pair of single-unit principal wall elements (Specimen 1) and specimen containing a pair of two-unit principal wall elements (Specimen 2). In this article, the results from the shaking-table tests obtained for Specimen 2 and numerically verified by using appro...
AbstractThis paper investigates the seismic analysis of multistory cross-laminated timber (XLAM) ... more AbstractThis paper investigates the seismic analysis of multistory cross-laminated timber (XLAM) buildings. The influence of different parameters such as wall geometry, vertical load level, friction, and, most importantly, connection stiffness, strength, and ductility is assessed. Linear and nonlinear finite-element (FE) analyses are carried out on a hypothetical 4-story case study building. The actual load-carrying capacity of the case study building is calculated with the nonlinear static pushover method and assessed using displacement-based design. The XLAM building behavior factors are then derived for different cases using a simplified method. Values in the range 2–3 have been obtained depending on whether monolithic or segmental walls (namely made of approximately 2-m-wide panels screwed to the adjacent ones) are used. Further nonlinear dynamic analyses carried out on a part of the case study building show that friction may have a beneficial effect on the seismic resistance of XLAM buildings. Howeve...
The paper investigates the influence of modelling different types of connections in multi-storey ... more The paper investigates the influence of modelling different types of connections in multi-storey cross-laminated ('crosslam') buildings when performing different types of analyses. More specifically, linear modal response spectrum analysis, nonlinear static (pushover) analysis assessed with a modified N2 method, and nonlinear time-history analysis are considered herein. In the research done by other authors, so far only the behaviour of certain types of crosslam building assemblies was investigated. In this paper it is shown how different connection details influence the building's global ductility and peak ground acceleration. Basic values of overstrength factors for BMF 105 angular brackets and 8 mm self-tapping screws are also presented and the importance of using the overstrength concept in design is demonstrated on a case-study wall.
The new structural systems consisted of solid cross-laminated wooden slabs are becoming more popu... more The new structural systems consisted of solid cross-laminated wooden slabs are becoming more popular as effective technology for construction of prefabricated medium-rise buildings. Austrian company KLH Massivholz GmbH produces large-sized cross-laminated wooden slabs in different number of layers and thickness which are used for all construction and non-construction building elements. As special attention is paid to buildings located in earthquake prone areas comprehensive research was done at University of Ljubljana FGG to set appropriate guidelines for design horizontal stability of KLH system. Shear walls are structural elements that are used to resist seismic and wind loads. In design of wood structures, the contribution of fenestrated wall segments usually is not taken into account when calculating the wall shear capacity. The load-bearing capacity and stiffness of fenestrated wood walls are influenced mostly by the size and layout of the openings. To evaluate the shear streng...
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The orthotropic properties of timber are well known - strong and stable along the grain, weak and susceptible to movement across the grain. Combining wood with other materials, to achieve composite action, enables the strength of wood to be realized and its shortcomings to be strengthened or eliminated.
COST Action FP1004, “Enhance mechanical properties of timber, engineered wood products and timber structures” provides a network for learning and development in a range of connected topics. This conference will present and record various methods for improving wood with other materials. It brings researchers and practitioners together to learn about various applications, and enables them to take part in discussions about future research and development.
The purpose of the COST program is to strengthen Europe and other countries in scientific and technological research, for peaceful purposes, through the support of cooperation and interaction between European researchers. This conference adheres to these principles. It will be an extraordinary opportunity to hear presentations from highly specialist, invited speakers and to participate in debate, in the island of Cyprus, which is located at the crossroads of three continents Europe, Asia and Africa in the Northern-east part of the Mediterranean Sea.
The orthotropic properties of timber are well known - strong and stable along the grain, weak and susceptible to movement across the grain. Combining wood with other materials, to achieve composite action, enables the strength of wood to be realized and its shortcomings to be strengthened or eliminated.
COST Action FP1004, “Enhance mechanical properties of timber, engineered wood products and timber structures” provides a network for learning and development in a range of connected topics. This conference will present and record various methods for improving wood with other materials. It brings researchers and practitioners together to learn about various applications, and enables them to take part in discussions about future research and development.
The purpose of the COST program is to strengthen Europe and other countries in scientific and technological research, for peaceful purposes, through the support of cooperation and interaction between European researchers. This conference adheres to these principles. It will be an extraordinary opportunity to hear presentations from highly specialist, invited speakers and to participate in debate, in the island of Cyprus, which is located at the crossroads of three continents Europe, Asia and Africa in the Northern-east part of the Mediterranean Sea.