The overriding purposes of this study were to determine the grammage dependency of structural and tensile characteristics of paper and to estimate the shear bond strength per unit area of paper. To accomplish these goals, an investigation into the close relationship between structural and mechanical characteristics of self-bonded ï¬bre networks were carried out. The microstructure parameters of handsheets were evaluated by conducting X-ray tomography experiments. Particularly, the relationship between thickness and grammage of handsheets was further examined. The test results provided that porosity is a grammage-dependent structural parameter. The porosity proï¬le and pore height distributions of handsheets were analysed by this approach. In addition, the eï¬ect of surface regions was discussed within this context. These results indicated that the role of the surface pore loses its importance along the thickness (z) direction of paper as the paper grammage is increased. The tensile results veriï¬ed that at a constant density, the mechanism of a sheet failure does indeed depend on sheet grammage. A wide range of relative bonded areas (RBA) was investigated including the critical relative bonded area (RBAcr). New estimations of critical bonding degree (CDB) were provided by failure transitions. The factors aï¬ecting this failure transition were presented in this thesis. These failure mechanisms within paper network were identiï¬ed and analysed by high-speed video techniques.