3　Subgrade Surface Treatment and Acceptance

3.1　Beam Surface Treatment and Acceptance

Beam surface treatment and acceptance mainly includes bridge plane position，bridge surface elevation，bridge surface flatness，height difference of adjacent beam ends and beam end flatness，waterproof layer quality，embedded parts on bridge surface（such as shear alveolus，lateral baffle alveolus），geometric size of alveolus，bridge surface cleanliness，and drainage slope on bridge surface，and so on.

3.1.1　Main technical requirement and inspection methods

1.Bridge surface elevation：the allowable error for bridge surface elevation 1.45m out of beam end shall be ±7mm，and positive error is not allowed within 1.45m of beam end.

2.Bridge surface flatness：3mm/4m，4m ruler shall be used for measurement（1m overlapping each time），every bridge surface shall be measured by four lines（0.5m left and right of the bed plate center）.Those which fail to satisfy 3mm/4m，but still within 8mm/4m shall be measured again with 1m ruler，and shall finally satisfy 2mm/1m.

3.Height difference of adjacent beam end：less than 10mm.

4.Beam surface flatness within 1.5m of beam end：the requirement is 2mm/1m，those which fail the requirement shall be polished and remedied until in compliance with the requirement.

5.Geometric state of embedded parts on bridge surface：the embedded parts shall be of correct plane and height position.The alveolus shall be finished and cleaned up.The composition of drainage ditch on bridge surface shall comply with design requirement.The expansion joint shall be installed in place and reliable.

3.1.2　Beam surface acceptance tools and instrument

The following tools and instruments shall be prepared for bridge surface acceptance：hammer，iron chain（around 2m，chain unit around 5mm），4m scaleplate，1m level bar，surveying wedge block，chalk，and blades.