According to the classification of instruments and equipment and respective descriptions , firstly ensure the service conditions , required horizontality and verticality , dryness , humidity and power voltage , pay attention to control vibration source and corrosive gas , and ensure clean installation environment , etc.
When the deviation between the placing position and construction reference line of caisson for gravity wharf is big enough , the verticality of upper structure , i.e. crest wall will be affected , and furthermore the visual quality of the wharf will be influenced .