New Zealand Society for Earthquake Engineering Conference
March 21-23, 2014, Auckland, New Zealand
This paper describes results of shaking table testing of a post-tensioned timber frame building in the structural laboratory of the University of Basilicata in Potenza, Italy. This experimental campaign is part of a series of experimental tests in collaboration with the University of Canterbury in Christchurch, New Zealand. The specimen was 3-dimensional, 3-storey, 2/3rd scale and constructed using post-tensioned timber frames in both directions. The structure was tested with and without dissipative steel angle reinforcing which was designed to yield at a certain level of drift. These steel angles release energy through hysteresis during seismic loading, thus increasing damping. Testing was performed up to a maximum PGA of 0.77g with and 0.58g without the dissipative reinforcing. At comparable levels of PGA the addition of the reinforcing reduced drifts by 32% without increases in peak floor accelerations. Test results were also compared favourable against numerical blind predictions using the RUAUMOKO 2D and SAP2000 structural analysis programs.
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 shaking table tests of a (strengthened) two-story reinforced concrete frame with and without infill are presented.
The proposed retrofit system employs a new outer cross laminated timber jacket to stabilise a building against horizontal shear forces that are caused by earthquakes; on one hand the timber panels have a low mass and therefore don’t contribute much to seismic forces, however they are very stiff on the other hand and provide high shear resistance. The new outer shell could have windows, doors and a façade installed already in the manufacturing plant. Another positive aspect of the outer shell is that there are no harsh interventions to a building and that people don’t have to move out during the construction phase (unlike when using most of the conventional methods for seismic strengthening). On the other hand the installation of panels is also possible from the inside with little influence on the existing structure. All together it makes a unique system that prolongs the lifespan of constructions, contributing to sustainability. In the following chapters the system is presented more in detail as well as the results from dynamic shaking table tests of a reinforced two-story RC frame with masonry infill.
New Zealand Society for Earthquake Engineering Conference
April 26-28, 2013, Wellington, New Zealand
Post-tensioned timber (PRES LAM) is a new form of seismic resistant construction which already has real building applications throughout New Zealand. The innovative high seismic performance system combines the use of precast concrete PRESSS technology and engineered wood products combining post-tensioning elements (providing recentring) with large timber members. Additional steel dissipation devices are often also placed in order to provide additional strength and dissipative capacity.
The following paper describes the design, fabrication and set-up of a dynamic testing campaign to be performed in the structural laboratory of the University of Basilicata (UNIBAS) in Potenza, Italy. The test specimen is a 2/3rd scale, 3-storey post-tensioned timber frame and wall are to be studied both with and without the addition of dissipative steel angles which are designed to yield at a certain level of drift in order to provide the desirable ‘flag shaped’ hysteretic response. These steel angles release energy through hysteresis during movement thus increasing damping as well as providing additional strength. The ratio between post-tensioning and energy dissipation provided will be altered between tests in order to investigate their contribution to dynamic frame performance. The specimen will be subjected to an increasing level of seismic loading using a set of 7 natural earthquakes selected from the European Strong Motion database.
This paper first describes the testing set-up, the fabrication of the test specimen and testing apparatus and the selection of cases which will be tested.
The material presented in this paper refers to a part of the investigation on cross-laminated (XLam) wall panel systems subjected to seismic excitation, carried out within the bilateral project realized by the Institute of Earthquake Engineering and Engineering Seismology (IZIIS) and the Faculty of Civil and Geodetic Engineering at the University of Ljubljana (UL FCGE). The full program of the research consista of basic tests of small XLam wooden blocks and quasi-static tests of anchors, then quasi-static tests of full-scale wall panels with given anchors, shaking-table tests of two types of XLam systems including ambient-vibration tests, and finally analytical research for the definition of the computational model for the analysis of these structural systems. In this paper, the full-scale shaking-table tests for one XLam system type (i.e. specimen 1 consisting of two single-unit massive wooden XLam panels) that have been performed in the IZIIS laboratory are discussed. The principal objectives of the shaking-table tests have been to get an insight into the behavior of the investigated XLam panel systems under seismic excitations, develop a physical and practical computational model for simutalion of the dynamic response based on the tests, and finally correlate the results with those from the previously performed quasi-static tests on the same wooden panel types. The obtained experimental results have been verified using a proposed computational model that included new contitutive relationships for anchors and contact zones between panels and foundations. Because a reasonable agreement between the numerical and experimental results has been achieved, the proposed computational model is expected to provide a solid basis for future research on the practical design of these relatively new materials and systems.
IOP Conference Series: Materials Science and Engineering
In recent years, development of wood engineering is gradually increasing. Instead of using many wood columns, cross laminated timber is expected for constructing spacious open space building. Since cross-laminated timber has high rigidity and strength, cross-laminated timber is expected to be used as earthquake resistant wall or floor diaphragm that makes the span of building can be increased and the position of the wall can be adjusted openly. In order to optimize the performance of cross-laminated timber for open space building, original cross laminated timber core structure method was developed. In this paper, the development concept of original cross laminated timber core structure method will be explained. In this method, the joint connection for each element such as joint connection for wall-concrete foundation, wall-beam, and wall to hanging wall was also developed. The experiment to verify the strength and rigidity of each connection has been conducted and the result will be described. The shaking table experiment of 3-story open space building constructed by original cross laminated timber structure using varies earthquake waves was conducted. In this experiment natural period, shear force for each floor, story drift, and building response data is taken. The result shows the structure designed by original CLT core structure method is satisfy the requirement based on Japan cross-laminated panel structure regulation.
This report is prepared for Softwood Lumber Board (SLB) by the NHERI TallWood Project team in order to provide a brief and timely update on the progress and preliminary research findings from the NHERI TallWood Project. This report is focused on the full-scale shake table test of a two-story mass timber building conducted during the summer of 2017 at NHERI@UC San Diego outdoor shake table.
The shake table test described in this report was conducted during a three-month period from June to August 2017. As the research team is still working on processing and analyzing the data obtained from the experiments, this report only discusses preliminary findings in a qualitative manner. The research team is expected to produce additional reports and publications based on the test results in the near future.
The national research project to investigate proper structural design method for CLT (Cross Laminated Timber) buildings has been advanced by the subsidy of the Ministry of Land, Infrastructure, Transport and Tourism of Japan since 2011. This paper provides the outline of shake table tests executed as a part of the project in February 2015. Two specimens, one (Specimen A) is five story and another (Specimen B) is three story, were tested. As the result, for both specimens damage was rather slight by the strong input wave according to the Building Standard Law of Japan. Finally, Specimen A survived three dimensional input wave of 100% of JMA Kobe (strong ground motion recorded during Kobe Earthquake in 1995), and Specimen B survived 140% of JMA Kobe.