// CODE SNIPPET

1812A.6 Inspection, Survey Monitoring and Observation

California Building Code 2016 (Vol 1 & 2) > 18A Soils and Foundations > 1812A Earth Retaining Shoring > 1812A.6 Inspection, Survey Monitoring and Observation

JUMP TO FULL CODE CHAPTER

The shoring design engineer or his designee shall make periodic inspections of the job site for the purpose of observing the installation of shoring system, testing of tie-back anchors and monitoring of survey.
Testing, inspection and observation shall be in accordance with testing, inspection and observation requirements approved by the building official. The following activities and materials shall be tested, inspected, or observed by the special inspector and geotechnical engineer:
1. Sampling and testing of concrete in soldier pile and tie-back anchor shafts.
2. Fabrication of tie-back anchor pockets on soldier beams
3. Installation and testing of tie-back anchors.
4. Survey monitoring of soldier pile and tie-back load cells.
5. Survey monitoring of existing buildings.
A complete and accurate record of all soldier pile locations, depths, concrete strengths, tie-back locations and lengths, tie-back grout strength, quantity of concrete per pile, quantity of grout per tie-back and applied tie-back loads shall be maintained by the special inspector and geotechnical engineer. The shoring design engineer shall be notified of any unusual conditions encountered during installation.
Calibration data for each test jack, pressure gauge and master pressure gauge shall be verified by the special inspector and geotechnical engineer. The calibration tests shall be performed by an independent testing laboratory and within 120 calender days of the data submitted.
Monitoring points shall be established at the top and at the anchor heads of selected soldier piles and at intermediate intervals as considered appropriate by the geotechnical engineer.
Control points shall be established outside the area of influence of the shoring system to ensure the accuracy of the monitoring readings.
The periodic basis of shoring monitoring, as a minumum, shall be as follows:
1. Intitial monitoring shall be performed prior to any excavation.
2. Once excavation has begun, the periodic readings shall be taken weekly until excavation reaches the estimated subgrade elevation and the permanent foundation is complete.
3. If performance of the shoring is within established guidelines, shoring design engineer may permit the periodic readings to be bi-weekly. Once initiated, bi-weekly readings shall continue until the building slab at ground floor level is completed and capable of transmitting lateral loads to the permanent structure. Thereafter, readings can be monthly.
4. Where the building has been designed to resist lateral earth pressures, the periodic monitoring of the soldier piles and adjacent structure can be discontinued once the ground floor diaphragm and subterranean portion of the structure is capable of resisting lateral soil loads and approved by the shoring design engineer, geo-technical engineer and building official.
5. Additional readings shall be taken when requested by the special inspector, shoring design engineer, geotechnical engineer or building official.
Monitoring reading shall be submitted to the shoring design engineer, engineer in responsible charge, and building official within three working days after they are conducted. Monitoring readings shall be accurate to within 0.01 feet. Results are to be submitted in tabular form showing at least the intial date of monitoring and reading, current monitoring date and reading and difference between the two readings.
If the total cummulative horizontal or vertical movement (from start of construction) of the existing buildings reaches ¹/₂ inch or soldier piles reaches 1 inch all excavation activities shall be suspended. The geotechnical and shoring design engineer shall determine the cause of movement, if any, and recommend corrective measures, if necessary, before excavation continues.
If the total cummulative horizontal or vertical movement (from start of construction) of the existing buildings reaches ³/₄ inch or soldier piles reaches 1¹/₂ inches all excavation activities shall be suspended until the causes, if any, can be determined. Supplemental shoring shall be devised to eliminate further movement and the building official shall review and approve the supplemental shoring before excavation continues.
Monitoring of tie-back anchor loads:
1. Load cells shall be installed at the tie-back heads adjacent to buildings at maximum interval of 50 feet, with a minimum of one load cells per wall.
2. Load cell readings shall be taken once a day during excavation and once a week during the remainder of construction.
3. Load cell readings shall be submitted to the geo-technical engineer, shoring design engineer, engineer in responsible charge and building official.
4. Load cell readings can be terminated once the temporary shoring no longer provides support for the buildings.