4.3　Soleplates and Pad Blocks

4.3.1　The location and loading of pad blocks shall comply with the following provisions in addition to the requirements in the technical documents of manufacturer:

1　They shall be arranged at locations of concentrated loads.

2　They shall be arranged on both sides of soleplate anchor bolts.

3　They shall be arranged at corners of soleplate.

4　The horizontal spacing of adjacent pad blocks should be 300mm-700mm.

5　Additional pad blocks shall be provided at stiffeners of soleplate as appropriate.

6　Static load of pad blocks shall not exceed 4MPa.

7　After completion of pad block mounting，the actual pad blocks layout drawing shall be drawn.

4.3.2　The following shall be completed before the turbine soleplate is installed in place:

1　The main dimensions of foundation shall be checked against the actual equipment，to make sure that installation requirements can be met.

2　The foundation concrete shall be roughened after removing the laitance layer，on the surface and concrete contaminated by oil shall be removed.

3　Foundation surface for pad blocks shall be chiseled to a new rough surface with exposed concrete aggregate，the pad blocks shall be in close contact with foundation，without warping at corners.

4　Locations for temporary pad blocks or adjusting jack shall be flat.

4.3.3　The form and material of pad blocks between foundation and soleplate shall comply with the following provisions:

1　Pad blocks shall be made of steel plate，forged and cast steel or cast iron，if special concrete mortar blocks are required by manufacturer，refer to Appendix A for the work requirements of mortar blocks.

2　For taper pad blocks，the thin edge thickness must not be less than 10mm，and the gradient shall be 1/10-1/25.

3　Pad blocks shall be flat and free of burrs，with 45°chamfer on edges of the plane，and the surface roughness of plane after machining shall not be higher than.

4.3.4　Installation of pad blocks shall comply with the following provisions:

1　Each set of pad blocks should not exceed 3，or not exceed 5 in special conditions，and only one pair of taper pad blocks is allowed.

2　The offset area of two taper pad blocks shall not exceed 25%of the area of the shim.

3　Soleplate and pad block and pad blocks of different layers shall be in close contact，the insertion length must not be greater than 1/4 of side length and insertion depth must not exceed 1/4 of lateral side length with a feeler gauge of 0.05mm.

4　Installation of embedded pad block is as shown in Fig.4.3.4，and shall comply with the following provisions:

1）The elevation of a pad block embedded along the longitudinal axial line shall comply with the requirements in technical documents of manufacturer，with permissible deviation of 2mm.

2）Thickness of the pad block should be greater than 20mm，and the longitudinal up-rising inclination of each pad block shall agree with that of the shaft system.

3）The grouting thickness at the bottom of pad block from roughened foundation surface shall be between 20mm-50mm，the grouting material shall be non-shrinking and test blocks shall be made under equal conditions.

5　After completion of pad block installation and before secondary grouting of foundation，the pad blocks shall be spot welded at lateral joints.

6　The position of supporting backing plates shall be correct for units installed with adjusting bolts and supporting back plates.

4.3.5　Anchor bolts shall comply with the following provisions:

1　Free of rust or oily dirt.

2　Nuts and bolts shall fit well.

3　The length and diameter of anchor bolts shall comply with design requirements，and the dimensions of their washers and backing plate center holes shall comply with requirements.

4.3.6　Installation of anchor bolts shall comply with the following provisions:

1　The gap of bolt in bolt hole or in bolt sleeve shall be greater than 5mm.

2　The permissible deviation of bolt perpendicularity is 5mm.

3　The backing plate at the lower end of bolt shall be flat，and in close contact with the foundation，the nut shall be locked and secured with spot welding；after final tightening，bolt shall have provision against loosening.

4　After tightening，the upper end of the bolt shall have 2-3 pitches of thread out of the nut，and the lower end thread shall be out of nut.

5　Anchor bolts shall be officially fastened after final locating of casing，and a feeler gauge of 0.05mm shall be used to check the sliding surface between the soleplate and bearing pedestals and casing，and the contact surface between pad blocks，and the results shall comply with the requirements in 4.3.4.When the anchor bolts are tightened，the load distribution values and center position of casing must remain unchanged.

4.3.7　Inspection and installation of soleplate shall comply with the following provisions:

1　The installation location and elevation of soleplate shall comply with design requirements，and shall comply with the following provisions if there is no design requirement:

1）The permissible deviation of bolt centerline is 2mm.

2）The elevation permissible deviation is 1mm.

2　The soleplate shall be in close contact with bearing pedestals，sliding block and casing，and there shall be no gap on the periphery of contact surface when checked with a 0.05mm feeler gauge.In checking the contact surface of cast iron soleplate with bearing pedestals or casing，the area with contact point in every square centimeter shall account for over 75%of total area and shall distribute evenly.

3　The soleplate shall be in close contact with the anchor bolt washers.

4　At locations where formwork cannot be set for secondary concrete grouting，before putting the soleplate in place，steel sheet stops shall be fitted on the inside of foundation，and the stops must not affect the expansion of casing and related pipes.

5　The concreting holes，vent holes and the lubricating oil injecting holes between soleplate and bearing pedestals or casing contact surface shall be through.

6　Any hole on soleplate with possible leakage of oil to concrete surface shall be plugged，and the plug must not restrict the expansion of bearing pedestals and casing.

7　The sliding surface shall be flat，smooth and free of burr，and there shall be no paint or dirt at the joint of soleplate and secondary grouted concrete.