Performance of Masonry Stone Buildings during the March 25 and 28, 2004 A?kale (Erzurum) Earthquakes in Turkey

This paper reviews the performance of stone masonry buildings during the March 25 and 28, 2004, A?kale (Erzurum) earthquakes. A?kale is a township located 35?km from Erzurum city in Turkey. A majority of the buildings in the affected region are built in masonry. Most of the masonry buildings were formed with random or coursed stone walls without any reinforcement supporting heavy clay tile roofing over wooden logs. A large number of such buildings were heavily damaged or collapsed. The cracking and failure patterns of the buildings are examined and interpreted relative to current provisions for earthquake resistance of masonry structures. The damages are due to several reasons such as site effect, location, and length of the fault, and the poor construction quality of the buildings. In addition to these reasons, the two earthquakes hit the buildings within three days, causing progressive damage. Low strength stone masonry buildings with mud mortar are weak against earthquakes, and should be avoided in high seismic zones.     

Design and Construction of a Bridge in Very High Performance Fiber-Reinforced Concrete

The design, technology, and construction of a small road bridge made of very high performance fiber-reinforced concrete is described in this paper. The bridge consists of precast prestressed concrete beams with a cast-in-place ordinary concrete deck. A preliminary experimental investigation was conducted to define the mix design, to establish the properties of the material and its durability, and to study the flexural behavior of the prestressed concrete beams with and without the concrete deck. The effect of steel fibers at the structural level, where there is an influence of constitutive behavior and size effects, was analyzed by testing a prestressed beam using very high performance fiber-reinforced concrete without fibers. The establishment of the structural properties of the material then allowed the design of the final section of the bridge beams and the definition of a model to justify the design rules adopted. This project represents an attempt to demonstrate the industrial feasibility of very high performance concrete structural elements manufactured with conventional raw materials and usual production techniques and to evaluate the production technology when utilizing steel fibers.     

Effect of Lamina Thickness on Parallel-to-Grain Strength in Small Douglas-Fir Samples

Timber has a rich history of use in bridge construction. Its small environmental footprint, pleasing aesthetics, long-term durability, and cost effectiveness assure its continued use for generations to come. That said, continued improvements in design, analysis, and construction with timber are highly sought. The inclusion of high-strength tensile-face laminations, such as fiber reinforced polymers, is increasingly common. This research investigated the impact of timber lamina thickness on axial compression strength parallel to the grain. Results showed that strength variability decreased with decreasing lamina thickness. This finding suggests that stronger and stiffer timber beams and stringers can be achieved by applying thinner wood lamina to the extreme compression faces. As such, the information contained herein can be used by glue-laminated-timber and fiber reinforced polymer/timber bridge designers to more effectively utilize wood as a structural material in bridges.