Based on different stress state at the cracking position and experimental results,an interface failure criterion was proposed.

The mechanism of the interface failure,as is reported in this paper, has been studied by the pull-out test, SEM, surf ace energy and fracture energy measurements.

Using the analytical methods of composite mechanics for reference, this paper established a layering shear-lag model accounting for the interfacial failure in mid-span and incorporated an energy failure criterion to study the stress redistributions and failure loads of carbon fiber sheet-reinforced concrete and reinforced concrete beams with a crack under 4-point bending.

By adopting a new anchoring method, interfacial failure happened between CFRP sheets and concrete, the effective jointing length between Sika~ CarboDur~ CFRP sheets and concrete is about 200 mm, and the interfacial bonding shear strength reached 20～30 MPa.

Microcosmic failure detection analysis and critical failure action for brittle rock;

Based on the balancing condition of internal forces in the case of balanced failure,the theoretical calculation formulas of limit values of axial compression ratio for core steel reinforced concrete(CSRC) columns are derived,and the main parameters which affect the limit values of axial compression ratio of CSRC columns are analysed.

Based on the balanced condition of internal forces in the case of balanced failure, the theoretical calculation formulas of limit values of axial compression ratio for steel reinforced concrete columns are derived.

The paper describes the conditions in which the different cases of balanced failure for steel reinforced columns may occur, and analyses the influences of different definitions about the case of balanced failure on the limit values of axial compression ratio for steel reinforced columns.