5　Brick Chimney Shell

5.1　General Requirements

5.1.1　Prior to the shell construction，the flatness of the top surface of the foundation circumferential shell or beam shall be inspected，and shall be leveled with 1∶2 cement mortar.The surface flatness must not exceed 20mm.The thickness of the mortar screed must not exceed 30mm.

5.1.2　Prior to the shell construction，the storey pole and the slope scale shall be established.

5.1.3　The centre and radius of the shell shall be inspected every 1.25m height during the construction.And the found deviation shall be corrected.

5.1.4　In the process of the shell construction，one group of testing mortar sample shall be taken on every 5m height.When the mortar strength or mixing ratio is changed，other testing samples shall be taken.

5.1.5　The positions，splices and anchorage length of rebar for the shell shall meet the design requirements.

5.1.6　The hoops installed outside the shell shall be level.The splice positions shall be staggered along the shell height.The hoops shall be painted with the anti-rust painting prior to the installation.In the process of installation，the bolts shall not be tightened until 40% of the mortar strength is reached，and hoops shall be clung to the shell.

5.1.7　The thickness of the bed joint，on which circumferential rebar is placed，shall be 4 mm greater than the rebar diameter.Above and under the rebar，there shall be 2 mm mortar at least.