Niclas Björngrim

Need for innovation in supplying engineer‐to‐order joinery products to construction: A case study in Sweden

Purpose – The construction industry has been criticized for not keeping up with other production industries in terms of cost efficiency, innovation, and production methods. The purpose of this paper is to contribute to the knowledge about what hampers efficiency in supplying engineer‐to‐order (ETO) joinery‐products to the construction process. The objective is to identify the main contributors to inefficiency and to define areas for innovation in improving this industry.Design/methodology/approach – Case studies of the supply chain of a Swedish ETO joinery‐products supplier are carried out, and observations, semi‐structured interviews, and documents from these cases are analysed from an efficiency improvement perspective.Findings – From a lean thinking and information modelling perspective, longer‐term procurement relations and efficient communication of information are the main areas of innovation for enhancing the efficiency of supplying ETO joinery‐products. It seems to be possible to make improvements...

Repairing of a timber truss through two different techniques using timber elements and screwed metal plates

Structural reinforcement of timber buildings may be needed due to different reasons such as change of use, deterioration due to lack of maintenance, exceptional damaging incidents or loading, after changes in regulatory specifications, or interventions to increase structural resistance. In this work, two different techniques were considered for repairing a timber truss that was previously assessed on laboratory (test facilities of University of Minho) and taken up to failure during a load-carrying test. A collar beam truss, with more than one hundred years, was tested considering a vertical point load on each main rafter. Failure of the timber truss was located in the sections of the rafters near the loading positions by bending. Repairing techniques, based on the use of timber elements for one of the rafters and on screwed metal plates for the other rafter, were evaluated and compared to the original unstrengthened condition. The efficiency of the combined repairing techniques was evaluated taking into consideration the structural performance of the collar truss, namely its displacement and ultimate load capacity. In this paper, the results of the experimental tests are discussed attending to the analytical calculation of the contribution of the repairing techniques. Also, the different failure scenarios, for original and strengthened truss, were analyzed and compared.

Engineered Wood in Cold Climate - Application to Monitoring of a New Swedish Suspension Bridge

Engineered wood is increasingly used in large structures in Europe, though little is known of its behavior in cold climate. This paper presents the structural health monitoring (SHM) system of a newly built suspension bridge with a deck of glulam timber as well as a bond stability study regarding cold climate performance of engineered wood. The bridge is located in Skellefteå in northern Sweden, and it connects two parts of the city situated on opposite shores of the Skellefteå river. In this ongoing study of the timber-bridge, a structural health monitoring system is employed to verify structural design and long-term performance. This 130m-span bridge is monitored using GNSS receivers, MEMS accelerometers, laser positioning systems, wireless moisture content sensors, strain gauges and weather stations. Data from the monitoring systems is analyzed regarding accuracy, complexity, costs and reliability for long time use. Engineered wood application in bridges, sports centers and timber buildings are discussed. Bond stability of glulam structures in cold climate is also examined in a range of experiments ranging from small glued wood joints to full size glulam bridge performance over time. From an engineered wood material point of view, the study is relevant to cold regions such as Scandinavia, Canada, Alaska, Russia, and the northern parts of China and Japan etc. The engineered wood constructions in these areas will be exposed to low temperature in a quite long period each year. The goal is to determine how engineered wood behaves when exposed to temperatures between 20 °C to -60 °C.