07 



materials, and careful installation and maintenance, this life is ncjt unreasonable. It is 

 assumed that in the case of each construction type the cost (jf construction is financed 

 by the sale of bonds bearing 5 per cent interest and maturing at the end of the assumed 

 life of the pier; that a sinking fund is established at the same rate of interest to retire 

 the bonds at maturity; and that a depreciation or replacement reserve is laid aside at 

 the same rate of interest for the purpose of reconstruction and returning loss of revenue 

 during the time of the reconstruction. The distance from the top of the piling or 

 cylinder to the water surface is taken at fi\e feet, the depth of water at 35 feet, and 

 the penetration of the piling at 35 feet. The construction costs are per square foot 

 of deck surface. 



Based on a twenty-five year life for creosoted piles, the figures show the annual 

 cost of all types for the same length of life. In addition to this the life of all other types 

 has been calculated from an annual cost corresponding to the annual cost of a creosoted 

 piling pier. 



ANNUAL COST, 25-YEAR LIFE 



TVl'K A 

 Creosoted piles, first cost $1.00 per square foot 



Interest on investment, at 5'^^c $0.0500 



Maintenance, at 5% . 0500 



Insurance 0066 



Sinking fund pa>ment .0209 



Depreciation reserve .0230 



Loss of revenue . 0063 



Total annual cost per square foot . 1568 



TYPE B 

 Reinforced concrete piles, first cost S2.00 per square foot 



Interest on investment, at 5% SO . 1000 



Maintenance, at 1% .0200 



Insurance 



Sinking fund payment 0.0419 



Depreciation reserve . 0503 



Loss of revenue . 0063 



Total annual cost per square foot SO .2185 



TYPE c 

 Reinforced concrete cylinders, first cost S3. 00 per square foot 



Interest on investment, at 5% SO . 1500 



Maintenance, at 1% 0.0300 



Insurance 



Sinking fund payment . 0628 



Depreciation reser\e . 0757 



Loss of revenue . 0063 



Total annual cost per square foot SO . 3248 



