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As long-term investigations are often too time- and cost-consuming, short-term experimentsare introduced for investigating the behaviour of connections in timber-concrete-compositeelements. The paper presents a proposal for short-term double shear tests with adhesive andmechanical connections for investigating their time-dependent behaviour. The proposedevaluation method determines the elastic and visco-elastic parts of the slip modulus of theconnection. The validity of the identified parameters needs to be verified by long-term tests.

As long-term investigations are often too time- and cost-consuming, short-term experimentsare introduced for investigating the behaviour of connections in timber-concrete-compositeelements. The paper presents a proposal for short-term double shear tests with adhesive andmechanical connections for investigating their time-dependent behaviour. The proposedevaluation method determines the elastic and visco-elastic parts of the slip modulus of theconnection. The validity of the identified parameters needs to be verified by long-term tests.

As long-term investigations are often too time- and cost-consuming, short-term experimentsare introduced for investigating the behaviour of connections in timber-concrete-compositeelements. The paper presents a proposal for short-term double shear tests with adhesive andmechanical connections for investigating their time-dependent behaviour. The proposedevaluation method determines the elastic and visco-elastic parts of the slip modulus of theconnection. The validity of the identified parameters needs to be verified by long-term tests.

As long-term investigations are often too time- and cost-consuming, short-term experimentsare introduced for investigating the behaviour of connections in timber-concrete-compositeelements. The paper presents a proposal for short-term double shear tests with adhesive andmechanical connections for investigating their time-dependent behaviour. The proposedevaluation method determines the elastic and visco-elastic parts of the slip modulus of theconnection. The validity of the identified parameters needs to be verified by long-term tests.

Rockbolts have been used to minimize the deformation of underground excavations where the surrounding rock masses contain weak planes such as fractures, joints or faults. Rockbolts installed across rock joints are able to resist the opening and shearing movements of rock joints. One of the rockbolt failure modes encountered in the field is caused by the excessive shear loads. A simple analytical model based on the Beam on Elastic Foundation (BEM) method is proposed in this study to predict the shear responses of a bolt installed perpendicularly to rock joint. The shear load-displacement curve of a double shear test can be divided into three stages: the elastic stage, the elasto-plastic stage and the plastic stage. The foundation stiffness for each respective stage are varied with the curvature influencing zone . The pretension effects are taken into account in the proposed analytical model. The model agrees well with the experimental shear tests, suggesting that the analytical model has the capability to predict the shear load-displacement curve of bolts crossing rock joints.

A large proportion of reinforcing elements in jointed rock mass can fail in shear. In the deep mines and rockburst-prone conditions, the bending and shear failure of rockbolts is also prevalent. This phenomenon has drawn greater attention and corresponding research has been conducted to investigate the shear performance of rockbolts. Nevertheless, the load transfer mechanism and the interaction between the rockbolts and rock mass were still not fully understood. Knowing both static and dynamic shear capacity of rockbolts and support systems is highly required to design the underground support rationally.The aim of this research is to provide a detailed analysis of shear behaviour of rockbolts using the laboratory tests and numerical modelling method approaches. Rockbolt and rock interaction, particularly near the shear joints, was investigated in this research. Four main parts were included in this thesis: static loading tests, numerical simulation under the static loading, dynamic loading tests, and numerical simulation under dynamic loading.A double shearing test (DST) system was used to examine the performance of rockbolt shearing. Testing was undertaken on certain strength concrete to simulate the rock mass. The laboratory test results reveal that rock strength, rockbolt diameters and installation angle, all affect the shear resistance of DST system by analysing the shear load-displacement relationships and the energy absorption abilities. It was found that rockbolts can increase the tension and shear properties of the surrounding rock mass. By comparing the DST results under static and dynamic loading conditions, it was found that the energy absorption ability of rockbolts is lower than under static loading condition. Thus, the dynamic performance of rockbolt is slight different with the static performance, which needs caution during the design of underground support in rockburst-prone condition.The numerical modelling technique was adopted to obtain the stress

Bolting is currently the most commonly accepted rock reinforcing method of dealing with rock strata instability in both surface and underground mines as well as civil engineering. Bolts are installed in fractured rock mass to build composite beams in weak strata or to attach weak excavation surfaces to deeper and competent rock layers to achieve stability. After opening, rock mass around the excavation space experiences stress redistribution and rock fracturing occurs in this process. Bolts installed in the fractured rock mass around excavations normally bear combined tensile and shear loads due to the opening and sliding of rock fractures. Direct shear restraint and high normal stress are applied by the bolt to the fracture surfaces to minimise their displacements. This mechanism allows the excavation surfaces to stabilise and makes them self-supporting. In the interactive process of rock mass and bolt, two load transfer mechanisms are involved: the axial tensioning (axial shearing at the bolt-grout interface, in essence) and the lateral shearing. Axial tensioning was the common focus in past studies, whereas lateral shearing is attracting more attention at present. The strength of the bolt when subjected to both shear and tensile loads is smaller than bolt strength when subjected to tensile load only. Thus, ignoring the shear load in bolting design probably leads to a higher safety factor. Hence, a deep understanding of bolt behaviour subjected to combined loads is essential in bolting system design and assessment. In the past, a number of experimental and theoretical investigations were conducted on the shear behaviour of the rock discontinuity reinforced by rock bolts and a few preliminary conclusions were drawn. Yet, few studies were performed on the shear behaviour of cable bolted rock discontinuities. Thus, this research investigated the shear performance of cable bolted rock discontinuities both experimentally and theoretically to provide more knowledge in t

Bolting is currently the most commonly accepted rock reinforcing method of dealing with rock strata instability in both surface and underground mines as well as civil engineering. Bolts are installed in fractured rock mass to build composite beams in weak strata or to attach weak excavation surfaces to deeper and competent rock layers to achieve stability. After opening, rock mass around the excavation space experiences stress redistribution and rock fracturing occurs in this process. Bolts installed in the fractured rock mass around excavations normally bear combined tensile and shear loads due to the opening and sliding of rock fractures. Direct shear restraint and high normal stress are applied by the bolt to the fracture surfaces to minimise their displacements. This mechanism allows the excavation surfaces to stabilise and makes them self-supporting. In the interactive process of rock mass and bolt, two load transfer mechanisms are involved: the axial tensioning (axial shearing at the bolt-grout interface, in essence) and the lateral shearing. Axial tensioning was the common focus in past studies, whereas lateral shearing is attracting more attention at present. The strength of the bolt when subjected to both shear and tensile loads is smaller than bolt strength when subjected to tensile load only. Thus, ignoring the shear load in bolting design probably leads to a higher safety factor. Hence, a deep understanding of bolt behaviour subjected to combined loads is essential in bolting system design and assessment. In the past, a number of experimental and theoretical investigations were conducted on the shear behaviour of the rock discontinuity reinforced by rock bolts and a few preliminary conclusions were drawn. Yet, few studies were performed on the shear behaviour of cable bolted rock discontinuities. Thus, this research investigated the shear performance of cable bolted rock discontinuities both experimentally and theoretically to provide more knowledge in t

Bolting is currently the most commonly accepted rock reinforcing method of dealing with rock strata instability in both surface and underground mines as well as civil engineering. Bolts are installed in fractured rock mass to build composite beams in weak strata or to attach weak excavation surfaces to deeper and competent rock layers to achieve stability. After opening, rock mass around the excavation space experiences stress redistribution and rock fracturing occurs in this process. Bolts installed in the fractured rock mass around excavations normally bear combined tensile and shear loads due to the opening and sliding of rock fractures. Direct shear restraint and high normal stress are applied by the bolt to the fracture surfaces to minimise their displacements. This mechanism allows the excavation surfaces to stabilise and makes them self-supporting. In the interactive process of rock mass and bolt, two load transfer mechanisms are involved: the axial tensioning (axial shearing at the bolt-grout interface, in essence) and the lateral shearing. Axial tensioning was the common focus in past studies, whereas lateral shearing is attracting more attention at present. The strength of the bolt when subjected to both shear and tensile loads is smaller than bolt strength when subjected to tensile load only. Thus, ignoring the shear load in bolting design probably leads to a higher safety factor. Hence, a deep understanding of bolt behaviour subjected to combined loads is essential in bolting system design and assessment. In the past, a number of experimental and theoretical investigations were conducted on the shear behaviour of the rock discontinuity reinforced by rock bolts and a few preliminary conclusions were drawn. Yet, few studies were performed on the shear behaviour of cable bolted rock discontinuities. Thus, this research investigated the shear performance of cable bolted rock discontinuities both experimentally and theoretically to provide more knowledge in t