149 



chaptp;r IX 



SERVICE RECORDS OE PILING IN 

 SAN ERANCISCO BAY 



By H. J. Wilson and C. L. Hill; 

 L. D. JuRs, Chairman of Siib-Comnnltee 



The tabulations making up this section, as has already been mentioned, represent 

 at least 90 per cent of the approximately quarter million piles located within San 

 Francisco Bay and tributary bay waters of sufficient brackishness to be subject to 

 borer attack. With very few exceptions they are limited to bearing piles only, fender 

 piles being subject to considerable mechanical damage and therefore not indicating 

 normal conditions in respect to borer attack. 



The data have been secured through the cooperation of owners and harbor en- 

 gineers, together with inspections by representatives of the Committee. Considerable 

 difficulty has been encountered in obtaining data on old structures, due to incomplete 

 records and the loss of old records in the fire of 1906. When not totally lacking, 

 records frequently omit critical data, such as materials used, dates of installation, or 

 dates and particulars of subsequent repairs or of removal and redriving of piles. 

 This has resulted in approximations as to number of piles and dates of construction in a 

 few cases and has curtailed the record of some redriven piles. But complete physical 

 inspections were made, either for the Committee or during the course of its study, on a 

 great number of structures, notably those of the State Harbor Commission and the 

 Southern Pacific Company. These are by far the largest two holders of piling structures 

 in this region, between them controlling about 60 per cent of all the piling in place. 

 It is believed, therefore, that the records as submitted are substantially correct. 



Two points merit special notice. The first is with respect to the disastrous record 

 of untreated wooden piling. The severity of the teredo attack upon these, in the 

 Carquinez Strait region where most of such piling was located, is borne witness to by 

 the fact that practically all of such piles, recorded in the 1920 service record work, 

 had failed and disappeared by the end of the next year. The second concerns the 

 record for creosoted piling, the large relative volume of which fairly reflects the pre- 

 dominance of this type of piling in these waters. 



In the following tables structures are listed, so far as possible, in geographical 

 order, beginning at the point of record farthest up the Sacramento River and pro- 

 gressing down-stream through the Carquinez Strait, thence southward on either 

 side, in turn, of the connected bays. For one unacquainted with the geography of 

 the region, this arrangement may make it somewhat more difficult to find specific 

 structures than under an alphabetic order, but it has been adopted so as to make 

 comparisons of ditTerent types of structures, in like waters, con\enient. The order of 

 tables corresponds to the order of discussion of each method of protection in the chapter 

 on Marine Substructure Materials, thus simplifying reference from one section to 

 the other. In any of the tables, for structures which show replacement or repairs of 

 piling, the history of the replacement or repair piling may be followed by turning to 

 the table for the kind of piling used in the replacement or repair, when that differs 

 from the original. 



It is believed that the volume of records warrants final conclusions respecting 



