Project Overview
Industrial and Commercial Bank of China Changzhou Branch Archives South Building renovation project construction area of 2438m2, from five-story teaching building into a file warehouse, due to the use of functional changes and the improvement of seismic retrofitting, Jiangsu Construction Engineering Design and Research Institute Co., Ltd. reconstruction calculation, the original teaching building part of the frame beam can not meet the requirements of the structural design specifications after the transformation, some of the frame beam must reinforcement. Two strengthening method: bonded steel plate reinforcement, strengthening with carbon fiber.

Structural Strengthening Material

The project selected FRP composite materials from Shanghai HORSE Construction Co., Ltd . Unidirectional carbon fiber cloth (high strength I), 12K, standard weight 300g / m2, thickness 0.167mm, tensile strength standard value ≥ 3400MPa, elastic modulus ≥ 240000MPa, elongation ≥ 1.7%. Carbon fiber structural adhesive for bonding carbon fiber cloth,A grade, tensile strength ≥ 40MPa, tensile modulus of elasticity ≥ 2500MPa, steel - Standard value of tensile strength of steel ≥ 14MPa, positive bond strength with concrete ≥ 2.5MPa, resistance to damp-heat aging (percentage of steel with reduced shear strength ≤ 10%), impact and peel resistance ( Average stripping length) ≤20mm.

Construction Quality Inspection 

1 Visual Inspection 

1.1 The visual inspection of the carbon fiber cloth immediately after the paste, requiring no gaps, lack of plastic area and folds. 

1.2 The presence of gaps or lack of plastic area should be added carbon fiber glue, the existence of wrinkled carbon fiber cloth should be removed after re-affixed. 

2 Metal Hammer Test 

2.1 The quality of the bond between the carbon fiber cloth and concrete The metal hammer can be used to test whether the reinforcing part of the carbon fiber cloth is hollowed out and the hollowing rate is not to be more than 5%. 

2.2 A single hollow area of not more than 10000mm2, injection can be used to fill plastic repair, ≥ 10000mm2 should be cut and repaired, the force direction of each end lap length ≥ 200mm, more than 3 layers of ≥ 300mm, non-force Direction is ≥100mm. 

3 Drawing Test On Site 

site drawing qualified indicators: the grass-roots concrete strength C15 ~ C20 is ≥ 1.5MPa, grass-roots concrete strength ≥ C45 ≥ 2.5MPa, grass-roots concrete strength between C20 ~ C45 linear interpolation to determine the pass indicators, and should Cohesive destruction of concrete. If unqualified, should be removed to re-affixed, and re-check acceptance.