Shear failure of the Meraka hardwood in bolted connections loaded parallel to the timber grain

This current study was conducted to establish a bolted connection experimental database on Malaysia woods. The effort of improving the retrofit guideline in designing the wall-diaphragm connections of masonry buildings can be continuously done. Brittle failure verifications on the Meraka hardwood to verify the occurrence of row shear failure are presented in this paper. The hardwood species was selected due to its common use as structural rafters and joists in the construction of roof and floor diaphragms of masonry buildings, respectively. Ten groups of a single row of steel-wood-steel (SWS) connections loaded parallel to the timber grain were tested. Each group was prepared with a total of ten replicates of specimens. Comparisons of bolted connection strength between the experimental results and the predictions of the existing design equations are discussed. It was found that the timber standard of Malaysia (MS544) too conservative in estimating the strength, whilst the Row Shear Model (RSM) is more comparative

Development of Consolidated Sarawak Geotechnical Site Investigation for Sarawak Soil

The development of spatial or non-spatial digitized Consolidated Sarawak Geotechnical Site Investigation (CoGSI) database aims to enable information to be stored in a digital form with the efficient search and fast retrieving data. The CoGSI database for Sarawak Soil is a function of a database management system, which consists of the site information; includes the project name, locations coordinates (division), borehole logs, field and laboratory test results. The main objectives of the project are to collect, store & digitized all verified & approved Geotechnical SI data and the input gathered from the local authority, consultants and contractors. The digitized database would be enormous value for future planning of infrastructure developments; making preliminary design estimates for earthwork/foundation assessment; and future decision making with early identification of potential areas for construction purposes, which will produce an economic and safe design. The SI databases are important resources where the insufficient ground conditions information, will cause either a significantly over-designed or an under-designed solution, which lead to potential failures. In addition, the project is also intended to realize a web-based application to allow users to search borehole, view bore-logs and provides digital downloadable boreholes data of the available ground information in a standard format for analysis. At present most of the SI data are available in the form of hardcopy reports, which is time consuming and often frustrating, especially when the required report or data cannot be found. In summary, the Consolidated Sarawak Geotechnical Site Investigation (CoGSI) database system, which stored in a digital format are deployed as a web-based system. This platform provides exploration of the digital databases, which then can be accessed anywhere and anytime through the desktop & portable computer and smart phones with internet access facility

Sri Aman peat: Settlement observation and geotechnical properties investigation

This paper presents the findings from the field observation and site exploration for construction on peat in Sri Aman, Sarawak, Malaysia. A visit to Balai Bomba and Pejabat Metrologi in Sri Aman has been done in August 2019. From the observation and measurement conducted on the two locations of the constructed area on peat shows the settlement, δ recorded ranges from 100 mm to 150 mm. A field sampling for the determination of geotechnical properties of peat has been done in Balai Bomba Sri Aman. The depth of the peat in the area is about 2.88 m and the results show that the peat has high natural moisture content ranges from 900 % to 1400 %. The organic content (OC) for the site is in the range of 70 %-90 % for a depth of 0.5 m to 2.88 m, and categorized as H3, fibrous peat except for the first 0.5 m is 63 % which fall under H5, hemic peat group according to Von Post classification

Snap-Back Testing and Estimation of Parameters for Nonlinear Response of Shallow and Pile Foundations at Cohesive Soil Sites

We are working on the development of methods for analysing the earthquake response of foundations that make use of Soil-Foundation-Structure-Interaction (SFSI) as a means of incorporating nonlinear soil deformation effects and nonlinear geometrical effects into the earthquake resistant design of foundations. There are three challenges in this work. First, to incorporate adequately the nonlinear response of the soil during the earthquake. Second, to account for geometrical nonlinearity during the earthquake - that is loss of contact between various parts of the foundation and the underlying and/or adjacent soil. Examples of this are the gapping that develops between a pile shaft and the surrounding soil during cyclic lateral loading and the uplift beneath parts of a shallow foundation subject to rocking. Third, to obtain appropriate values for the soil parameters which describe the nonlinear response of the foundations. The main thrust of this paper is to show how snap-back testing is a most effective means of evaluating nonlinear soil behaviour. It will be demonstrated that snap-back testing is more convenient than using a shaking machine which applies sinusoidal excitation. The results will show how for the rocking of a shallow foundation and the cyclic lateral loading of a single pile, the damping and the stiffness can be estimated at increasing levels of lateral loading

Lateral Dynamic Response of a Single Pile Model

The dynamic response of a single pile with an attached mass giving a single degree of freedom (SDOF) system subjected to lateral pile-head loading is described. Two types of dynamic tests were performed, primarily free-vibration and dynamic forced-vibration tests. The main aims of this paper were to provide a basic understanding of the single pile head action and to evaluate the applicability of the elastic continuum method (ECM) in estimating the dynamic parameters of the pile-soil system. The single pile model was constructed using an instrumented steel pipe with an outside diameter of 50.65 mm and a wall thickness of 1.05 mm. The measured data from the frequency domain analysis were analysed to determine the natural frequencies fn, damping ratios ζ, and lateral pile-mass connection displacement uLat of the pile-soil system. The experimental results obtained were then compared with those calculated from the analytical calculation based on the ECM. The analytical prediction was based on a perfect pile-soil bonding with the pile embedded in a homogeneous soil layer with a constant Young’s modulus with depth. The natural frequency obtained from the free-vibration test was greater than that from forced-vibration test. This was found to be in general agreement with other related published works. The experimental and analytical results were shown to be reasonably matched, thus, the ECM demonstrates a good potential application in estimating the dynamic parameters and the lateral displacement

Assessing the Bolted Connection Strength of New Zealand Hardwood

From published literature, it was found that through-bolt connections were typically applied as a retrofit technique to most New Zealand unreinforced masonry (URM) buildings following the 1931 Hawke’s Bay earthquake. As connection failure by tearing out part of the diaphragm joist was observed in past earthquakes due to lateral earthquake loading, the strength of the bolted connection in existing indigenous New Zealand timber joists needs to be assessed. The main objectives of this study were to evaluate the strength and to identify the possible failure modes of bolted connections in New Zealand hardwood. Bolted connection tests loaded parallel-to-grain were performed using recycled native New Zealand Matai and Rimu hardwoods because the timber diaphragms in URM buildings are typically constructed using such wood species. From the experimental study, it was observed that the timber bolted connection can fail in either ductile or brittle modes. The test results obtained were compared with the European Yield Model (EYM), the New Zealand timber code (NZS 3603:1993), and a proposed set of equations (Quenneville 2009) in order to evaluate the applicability of those equations in predicting bolted connection strength for New Zealand hardwood. It was found that the EYM equations provide better predictions than the NZS 3603:1993 when compared to the actual capacity. However, the EYM predictions are only good in estimating the strength of timber bolted connections that fail under ductile mode. For the connections that fail exhibiting the brittle mode, the proposed row shear equation by Quenneville was found to give better strength estimation

Strength Assessment of Typical Wall-Diaphragm Connections in New Zealand URM Buildings

Most unreinforced masonry (URM) buildings in New Zealand consist of solid URM bearing walls and flexible timber diaphragms (floor and roof), and insufficient or absent positive anchorage between URM walls and diaphragms has previously been identified to be the most common reason for out-of-plane wall and gable failures in URM buildings during earthquakes. A series of case studies was performed to determine typical details for wall-diaphragm connections, to ensure that realistic specimens were reproduced in laboratory testing to accurately assess their strength. It was found that typical wall-diaphragm connections in New Zealand were through-bolt anchors, where one end of a threaded steel rod was bolted with a steel bearing plate at the exterior face of the URM wall and the other end was welded to a rectangular steel plate that bolted to the timber joist. This type of anchor was believed to be applied as a retrofit technique to most New Zealand URM buildings following the 1931 Hawke’s Bay earthquake. In order to assess the strength and possible modes of failure of the wall-diaphragm connections, two types of testing were conducted as follows: (1) pull-out tests on URM wall with typical through-bolt anchor type; and (2) bolted timber connection tests loaded parallel to the timber grain