Quality Of Bolts Research Articles

An experimental investigation into failure mechanism of a full-scale 40 m high steel telecommunication tower

The main objective of this paper is to present and discuss failure mechanism, failure mode, as well as plastic deformation of a lattice telecommunication tower obtained during a full-scale pushover test. The manuscript consists of a detailed description of the tested structure and the experimental site. Displacements of particular nodes of the tower are presented as a function of the external load. The main conclusion is that the rigidity of joints between particular elements, which depends on thickness and diameter of connecting flanges and number and quality of bolts, determines the failure mode of the compressed tower legs. In the article, values of axial forces under compression, taken directly from the conducted test, were compared with the standard buckling resistance. On the basis of this comparison, discussion about the effective slenderness factor has been generated, and the proper determination of this coefficient has been proposed.

Identification for Bolt-Surrounding Rock System Based on Wavelet Neural Network

The dynamic testing is widely used in undestructive testings of bolt’s anchoring quality. But it’s difficult to estimate bolt’s anchoring quality according to the dynamic response of bolt. The bolt’s anchorage quality depends mainly on bolt-surrounding rock structural system which features must be identified. A new analytical method used in identification for bolt-surrounding rock structural system is put forward, which combine with advantages of wavelet analysis and artificial neural network. The results indicate that this wavelet neural network after training can best identify the bolt’s side rigidity factors and can be a useable intelligentized mean to assess the quality of bolt’s anchoring system.

Application of Geo-Synthetic Technology for Erosion Control of Tana Lake Catchment Areas and Blue Nile Banks

In steel construction, the importance of connection cannot be overemphasized. Steel connection can be made of bolts, rivets and welding. The quality of bolts, rivets and welds in structural steel connection affects the connection and hence the capacity of the whole steel structure. This paper examined the quality of bolts and nuts available in the Nigeria market. Samples of bolts of diameters 10mm, 12mm, 16mm and 20mm were sourced from five providers in Lagos State. After testing the samples for both tensile and shear strengths, it was established that only 10mm and 12mm diameter bolts meet the grade 4.6 requirements of 195N/mm2 and 160N/mm2 for tensile and shear strengths respectively. For 20mm diameter bolts, only specimens from providers B, C and D meet the code requirements for both tensile and shear strengths for grade 4.6 bolts. Keywords: Shear, Bearing y, Tensile, Capacity, Connections, Bolts, Rivets, Welds. African Research Review Vol. 2 (4) 2008: pp. 186-197

Engineering Properties of Bolts and Nuts in Lagos State, Nigeria

In steel construction, the importance of connection cannot be overemphasized. Steel connection can be made of bolts, rivets and welding. The quality of bolts, rivets and welds in structural steel connection affects the connection and hence the capacity of the whole steel structure. This paper examined the quality of bolts and nuts available in the Nigeria market. Samples of bolts of diameters 10mm, 12mm, 16mm and 20mm were sourced from five providers in Lagos State. After testing the samples for both tensile and shear strengths, it was established that only 10mm and 12mm diameter bolts meet the grade 4.6 requirements of 195N/mm2 and 160N/mm2 for tensile and shear strengths respectively. For 20mm diameter bolts, only specimens from providers B, C and D meet the code requirements for both tensile and shear strengths for grade 4.6 bolts. Keywords: Shear, Bearing y, Tensile, Capacity, Connections, Bolts, Rivets, Welds. African Research Review Vol. 2 (4) 2008: pp. 173-185

Quality of bolts made from rod produced on the OAO MMK 370 mill

Quality of bolts made from rod produced on the OAO MMK 370 mill

Impacts of gloving and un-mixed resin in fully encapsulated roof bolts on geotechnical design assumptions and strata control in coal mines

Modern strata control practices utilising resin encapsulated roof bolts has been adopted in high productivity coal mining operations as the primary means of reinforcement. The geotechnical design of safe and fit-for-purpose underground excavations relies on many design assumptions regarding the effectiveness and load transfer characteristics of the installed reinforcement. The effectiveness of the installed roof bolts can be compromised by glove fingering (gloving) of the resin cartridge and un-mixing of the resin mastic, resulting in a reduction in the load transfer characteristics of the roof bolts, and ultimately, compromising the design assumptions used. Following a routine installed bolt quality audit and some small roof falls containing gloved bolts across a range of mine sites involving many geological and geotechnical conditions, a work programme was initiated to determine the extent of the gloving and un-mixing problem and to develop an understanding of mechanisms involved. Results have shown that gloving and un-mixing is a systematic and widespread phenomena, occurring across the range of resin and/or bolt manufacturers, and in a variety of roof types. Gloving was found in bolts installed using either hand held pneumatic or continuous miner-mounted hydraulic bolting rigs, under face conditions by operators, and under controlled manufacturers “best practice” conditions. Research has been undertaken using recovered bolts from various mine sites, as well as test bench trials and the quantification of the loading characteristics of gloved bolts using strain-gauged roof bolts. To understand the impacts of gloved bolts and un-mixed resin on the geotechnical design assumptions used a FLAC 2D numerical simulation was undertaken. The results provided an insight into the way the roof bolts interact, the resultant failure mechanisms/pathways and provided quantification of deformation levels and reinforcement requirements. The results being incorporated into the strata management plans.