4.5　Shim

4.5.1　The total area of the bottom of shim group shall be calculated and determined according to such factors as the equipment weight and production load，the tightening force of anchor bolts，and the compressive strength and safety factor of foundation concrete.

4.5.2　The shim shall be arranged at main stressed parts of the equipment base，preferably one or both side（s）nearby the anchor bolts.In case that seams exist on the equipment base，both sides shall be arranged with shim.Two adjacent groups of shims should keep the distance of not more than 1，000mm，and the part under the base shall cover the center of the anchor bolt.

4.5.3　After the equipment has been aligned and leveled and the anchor bolts have been tightened，every group of shims shall be compressed tightly，which can be checked and determined by listening to the sound after hammering.The shims for equipment operating at high speed or subject to impact shall be checked with 0.05mm feeler gauge at the same cross section of them，and the total length of inserted parts at both sides must not be more than 1/3 of total length of the shim.After completion of equipment installation，every group of shims shall be firmly connected together by tack welding.

4.5.4　The mounting of shims by grinding shall meet the following requirements:

1　It is required to remove the laitance from the surface of the foundation，and then chip and grind its part for mounting shim.

2　The shims shall be mounted stably and orderly with uniformly distributed contact points with the foundation.The shims and the equipment base shall keep in good contact with each other.

3　One group of shims should consist of flat shims and inclined shims，with the quantity not more than five pieces in total.The inclined shims shall be put above the flat ones.

4.5.5　The construction process of installing shims with bed-mortar method shall meet the requirement of the design technical document，or related requirements of the current national standard General Code for Construction and Acceptance of Mechanical Equipment Installation Engineering（GB 50231）in case of no related requirement in the design technical document.

4.5.6　If the requirement for setting of cushion block is specified in the design technical document，it is required to comply with the requirement as specified.