Tension control bolts (TC bolts) are specialized fasteners mainly utilized in steel frame construction. They include a pre-assembled bolt, nut, and washer for simplified installation. In contrast to standard bolts, TC bolts have a domed head and a distinctive spline design that enables accurate tensioning during the installation process. This advancement has led to their growing popularity in the construction sector because of their effectiveness and dependability. In this article, examined this type of bolts, installation mechanism, their advantages over conventional High-strength structural bolts, challenges and considerations, durability comparison between traditional and TC bolts, design features, installation process, and also review the relevant standards associated with them.

With growth the construction technologies, Cold-Formed Steel, CFS, sections are widely used in ordinary steel buildings because of some advantages such as light weight, ease of installation, decrease in cost, and increase in speed of operation. Using the bolted connections for CFS joist is one of the best details for steel structures. The main objective of this study is to conduct an experimental research to evaluate the load carrying capacity of bolted connections based on various bolts arrangement. Ten full scale joist-beam connections are tested under the incremental gravity load. The variable parameters are the arrangement of bolts, and thickness of CFS sheets. The joist sections made of two C-shaped, which are back-to-back connected using self-drilling screw bolts in the web. The arrangement of bolts connection and steel sheet thickness are considered as two major factors to improve the load carrying capacity. Base on the obtained results, it was observed that increasing the number of the bolts and their spacing from the neutral axes led to the additional load carrying capacity. Furthermore, it can be concluded that the thickness of CFS sheets play an effective role for load carrying capacity of connections.

With careful design, mixed microstructures consisting of fine plates of upper bainitic ferrite separated by thin films of stable retained austenite have exhibited impressive combinations of strength and toughness in High-silicon bainitic steels. The silicon suppresses the precipitation of brittle cementite leading to an improvement in toughness. The essential principles governing the optimization of such microstructures are well established, particularly that large regions of unstable High-carbon retained austenite must be avoided. The aim of the present work was to see how far these concepts can be extended to achieve the Highest ever combination of strength and toughness in bulk-samples, consistent with certain hardenability and processing requirements.  

This paper presents the results of an experimental investigation carried out to evaluate the shrinkage of High strength Concrete. High strength Concrete is made by partial replacement of cement by flyash and silica fume. The shrinkage of High strength Concrete has been studied using the different types of coarse and fine aggregates i.e. Sandstone and Granite of 12.5 mm size and Yamuna and Badarpur Sand. From the test results of the above investigation it can be concluded that the shrinkage strain of High strength Concrete increases with age. The shrinkage strain of concrete with replacement of cement by 10% of Flyash and Silica fume respectively at various ages are more (6 to 10%) than the shrinkage strain of concrete without Flyash and Silica fume. The shrinkage strain of High strength Concrete is also compared with that of normal strength concrete. Test results show that the shrinkage strain of High strength concrete is less than that of normal strength concrete.      

Steel industries produce Ground Granulated Blast Furnace Slag (GGBFS) as a waste material and have a High potential for producing concrete as a partial substitute for cement. The average particle size of GGBFS used was 17. 5  m. It fills voids and modifies the microstructure and, in turn, enhances the strength and durability of concrete. In the present work, commercially available ultrafine slag (ready-made ultrafine slag (RUFS)) with an average size of 5  m was used as a mineral admixture with three different percentages of 30, 40, and 50 as substitutes for cement. Results of the present work were compared to the precursor slag of this author's earlier works. According to the experimental results, it was understood that RUFS with 40% substitution for cement obtained better performance among three different percentages used. Compared with the author's earlier works, RUFS performed better than precursor slag and had slightly Higher results than that of concrete with 5 to 15% of RUFS. Hence, it is suggested that cement may be replaced with Highvolume ready-made ultrafine concrete by 40% without compromising its performance.