Frequently Ask Questions

Q: How much hammer weight do we need to conduct PDA Test?
A: Minimum 1% - 2% of pile ultimate capacity, 2% is recommended for long and high capacity of pile

Q: What is the right time to conduct the PDA test?
A: For driven pile, PDA test can be conducted directly after pilling if meet the final set criteria, for bored pile is highly recommended after concrete strength achieved minimum 85%.

Q: How many piles should be tested?
A: These regulation can be seen on SNI 8460:2017 Chapter 9.8

Q: Can we use direct capacity (RMX/RSU value) as final pile capacity?
A: For long, non uniform, high capacity pile and various soil stratum, RMX value can't be used as final capacity, as RMX value only valid on uniform pile and relatively uniform soil condition. Please noted only use capacity from CAPWAP analysis result.

Q: How is the pile preparation for PDA test?
A: For both driven and bored piles, ensure pile head is level. For bored pile, it's critical to ensure the pile head is sound concrete unless hammer impact will break the pile head. For the height of pile, it's required minimum 2D.

Q: What happened if the pile head broken and required capacity not yet achieved?
A: Its refusal capacity, means the pile still has immobilized capacity, in order to mobilize higher pile capacity, higher energy required (higher drop height) but since the pile head already broken the test can't be continued.

Q: is the CAPWAP capacity equal to pile ultimate capacity?
A: Pile capacity from CAPWAP analysis is yet mobilized ultimate pile capacity.

Q: How to get real pile ultimate capacity with PDA test?
A: Pile ultimate capacity means all capacity from friction and end bearing, to mobilize both capacity we need to ensure pile toe is move and occurred permanent pile head settlement. To perform the test, 2% or more of hammer weight is required.

Q: Can PDA test conducted on raked pile?
A; Yes, it can.

Q: Can PDA test conducted on wooden pile?
A: PDA tes can be conducted on certain varieties of hard wood (e.g. Ulin wood) as long as we can check the actual wavespeed on it by conducting PIT test on pre-installed pile.

Q: How long it takes to test one pile?
A: From preparation until finish testing took about 30 minutes for driven pile, and 1~2 hours for bored pile.

Q: How many blow it needed each test?
A: Based on ASTM D4945, preferably apply series of single impact blows, beginning with low drop height to check transducer function and pile stresses and then progressing to greater drop heights to mobilize additional pile capacity.

Q: Can it conducted on composite pile?
A: PDA test can be conducted both on concrete or steel piles also applicable on composite concrete and steel piles.

Q: What is the right time to conduct the PIT test?
A: For driven pile, PIT test can be conducted directly after pilling and for bored pile it is highly recommended after concrete strength achieved minimum 85% and ensure pile head is sound concrete.

Q: How many piles should be tested?
A: Please refer to SNI 8460:2017 Chapter 9.8 or designer spesification if any.

Q: Can PIT determine the caused of pile integrity issue?
A: No it can't. PIT merely check pile potential integrity issue and describe it as impedance reduction. Impedance is a function of pile area and modulus. In other words PIT can't determine whether it's caused by area reduction and/or low concrete quality.

Q: Can PIT detect actual pile length?
A: Based on relation of wavespeed and arrival time, length of pile can be detected but this condition required clear pile toe during the test, however please notice that PIT has several limitation as it affected by soil resistance thus could affect not clear toe response as well as wrong wavespeed could result wrong interpretation.

Q: Can pit detect longitudinal crack?
A: It can't, as the stress wave travel a long the pile, wave will reflect only if encouter crack across pile section that create gap.

Q: Can PIT detect the pile splice?
A: Yes it can, but since the pile splice has material change (concrete to steel) and sometimes there were gap between joint plate even it was fully welded, PIT will notice it as impedance reduction. In this case PDA test is more reliable to check pile splice.

Q: What is the next step if there was indication of defect pile?
A: It is advisable to consult the issue with designer and consultant whether is it necessary to take remedial action or perform capacity test based on defect evaluation.

Q: Can PIT perform at pile cap?
A: It can't, PIT can only be conducted on single actual pile head, but for suspended pile cap (e.g. pile slab, jetty, etc) with exposed pile segment, PIT can still be performed using side attached sensor. But this method has lower accuracy than top mounted sensor.

Q: How many piles can be tested a day?
A: Assuming pile head and concrete quality is good enough, it can be done 10 ~ 15 piles a day.

Q: Is there any correlation between PIT result to pile capacity?
A: PIT only detect pile integrity issue without any pile capacity information.

Q: Can PIT be done on steel cap e.g. spun or square driven pile?
A: For most case, it works on spun pile, but on square pile the steel cap shall be removed and test on concrete surface instead.

Q: What is the right time to conduct the CSL test?
A: CSL test can be conducted prompt to 3 - 7 days after casting. But it's highly recommended to conduct the test after 7 days to prevent slow hidration process that might caused false indication of low concrete quality.

Q: How many piles should be tested?
A: These regulation can be seen on SNI 8460:2017 Chapter 9.8

Q: Can we use PVC pipe for CSL test?
A: It's not recommended to use PVC pipe as it can shrink due to concrete hydration heat and create debonding effect. Steel or black steel pipe is recommended.

Q: What is debonding?
A: Debonding is bonding loose between concrete and pipe that create gap inbetween. This gap lead to ultrasonic wave can't transmit trough and result 'false bad concrete' indication.

Q: What if PVC already used?
A: Ensure to circulate water inside the pipe to neutralize heat from hydration.

Q: What if one of the pipe is blocked?
A: The test still can be conducted but the trace correlated to that blocked pipe can only be tested up to accessible depth.

Q: What if there is no water inside the pipe?
A: The test can't be conducted as CSL transmit ultrasonic wave that can't transmit through air.

Q: What if the pipe is filled with mud?
A: It's mandatory to flush the pipe and ensure the pipe only fill with clean water. Dirty or contaminated water could disturb ultrasonic wave.

Q: What pipe diameter should be used?
A: Minimum 2" (5cm).

Q: How many pipes should be installed?
A: Minimum 3 pipes for 80 cm of diameter and lower, 4 pipes for 80 cm and larger. For pile larger than 150 cm, 5 or 6 pipes is recommended.

Q: Where to install the pipe?
A: The pipe shall be installed inside rebar cage and arranged evenly.

Q: Can CSL test evaluate concrete cover?
A: No it can't, to evaluate concrete cover Thermal Integrity Profiler is the suitable test.

Q: How many piles can be tested a day?
A: Average pile with 30 m depth with 4 pipes can be done 6 ~ 8 piles a day. More than 50 m depth and 5 pipes, about 2 ~ 4 piles a day.

Q: What TIP test can evaluate compare to the PIT and CSL?
A: TIP can determine size and location of defects, like determining cover, radius, and cage alignment in 3D visualization.

Q: How TIP can evaluate defect on pile?
A: By evaluating temperature during concrete hydration, TIP infrared sensor measure local temperatures as a function of depth. As there is no defect the average temperature of the concrete should be uniform. In other words, lower temperature indicates defects, low concrete quality or thinner concrete cover, while higher temperature indicates bulged or thicker concrete cover.

Q: How to perform TIP test?
A: TIP test required preinstalled access tube like CSL test. Unlike CSL test, PVC tube is considerably good for TIP test since the test based on temperature measurement. After finish casting concrete, fill the pipe with water and leave it for about 12~36 hours afterwards the test can be conducted.

Q: How many pipe should be installed?
A: Similar to CSL, minimum 3 pipes for 80 cm of diameter and lower, 4 pipes for 80 cm and larger. For pile larger than 150 cm, 5 or 6 pipes is recommended.

Q: What is the advantages of TIP compare to the CSL?
A: Talking about the time, TIP can be conducted relatively 12 hours after finish casting and it means direct evaluation of the construction method can be evaluate sooner. TIP result can detect accurately pile defects such as cover loss, necking, and pile rebar alignment in 3D visualization.

Q: Is KODEN/SHAPE similar to Ultrasonic Drilling Monitor (UDM)?
A: Yes it's the same, KODEN/SHAPE is merely product name for ultrasonic drilling monitor.

Q: What is UDM?
A: UDM is a test to evaluate drilled hole alignment as well as hole diameter.

Q: What is the different between KODEN and SHAPE?
A: Basically these two equipment is the same, KODEN can only check two axis and evaluate result in 2D graph, while SHAPE can evaluate in six axis and present the result in 3D visualization however SHAPE can't be used for diaphragm wall as it need to attached on kelly bar.

Q: Can we get direct result after the test?
A: Yes, after finish the test, result can be seen directly on equipment monitor.

Q: How long it takes to performed the test?
A: It took about 30 minutes prior to each test.

Q: Can it performed on dry shaft hole?
A: No it can't, both equipment works with ultrasonic sensor, without any liquid (water or slurry) ultrasonic wave can't works.

Q: What is the minimum and maximum diameter can be detected?
A: It can performed on minimum 50 cm diameter of shaft and with higher gain and relatively clean water or slurry, it can performed up to 6 m diameter.

Q: What is the maximum settlement for compression, tensile, and lateral load test.
A: Based on SNI standard, maximum settlement for compression load test is 25mm for pile below 80 cm diameter and 4% x D for pile larger than 80 cm on 200% load. For tensile and lateral load the maximum displacement is 25 mm for all pile diameter. Please noted this standard is not mean to be stricted, designer might state their own standard based on their own pile design.

Q: What if the actual pile top is too deep? can the pile load test conducted on actual ground level?
A: Yes it can, but on SNI mentioned for deep cut of level, pile section above C.O.L should be treated to reduce skin friction (debonding). But for lateral test, it should be conducted at design pile head level (at C.O.L).

Q: What is the debonding method?
A: There are several method for debonding such as prebore and cover the pile with geosynthetic material prior to pile instalation. It is highly recomended to check the effectiveness of those method by conducting instrumented load test.

Q: How long is the testing time?
A: For testing time only with 200% load schedule (exclude equipment setup), compression and tensile took about 36 hours, and 7 hours for lateral test.

Q: How to conduct tensile load test on spun pile or square pile?
A: We will use special connector (anchor wedges) to tie up the pc wire or strand so it can be pulled up.

Q: Is Bi-directional load test accepted in Indonesia?
A: Refer to the SNI 8460:2017, static axial load test can be conducted using one of these following method, first is kentledge, second is reaction pile, third is bi-directional load test.

Q: Is it applicable for driven pile?
A: For now, it is only applicable for bored pile.

Q: Should the jack installed at the bottom of the pile?
A: It require several analysis where to install the jack to ensure it has equal upward and downward capacity so it's not always to put the jack at the bottom.

Q: What if the pile is already constructed? Is this method still can be done?
A: As the jack need to be installed inside the rebar cage, finished bored pile can olny be tested with kentledge or reaction pile method.

Q: Is there any minimum pile diameter?
A: Since the jack is available for costum, it can be done to all pile diameter.

Q: What are the advantages of bi-directional load test?
A: Compare to other two methods, it is safer, time-savings and it doesn't require large space. For high load and remote area project it's cost-saving method.

Q: What is the right time to conduct the test?
A: It's recommended to conduct after 28 days of concrete age but if any other design consideration it can be conducted sooner or later as-per designer specification and approval.

Q: Can inclonemeter be installed on retaining structure?
A: Yes, it can be installed both on soil and retaining structure.

Q: Does PVC pipe can be used as inclinometer pipe?
A: Inclinometer pipe required special grooved pipe as guide for the inclinometer probe. We provide ABS resin inclinometer pipe to meet its requirement. You can check our inclinometer pipe sepcifiaction here.

Q: How deep is inclinometer pipe to be installed?
A: Inclinometer pipe should be installed at sufficient depth where the tip part will not be affected by anticipated displacement (slip zone).

Q: Is there any local standard for Inclinometer?
A: For Indonesia, there is SNI 3404:2008.

Q: What type of piezometer is used?
A: We are using vibrating wire piezometer sensor from Geokon.

Q: Is vibrating wire piezometer and pneumatic piezometer same?
A: Yes it is, both type measuring total pore pressure at specified depth. The difference between those two is only measuring principal, which are using vibrating wire and pneumatic gas pressure.

Q: What are advantages of vibrating wire?
A: It's highly accurate, robust and fast measurement compare to the pneumatic piezometer.

Q: Can piezometer measure excess pore pressure?
A: Yes it can, if static ground water level is known. As we know excess pore pressure can be calculate by eliminating total pore pressure with static pore pressure.

Q: How to measure the static ground water level?
A: It simply by installing observation well.

Q: What is the maximum capacity of the piezometer?
A: It available from 100 kPa up to 20 MPa.

Q: Can it be done using remote monitoring?
A: We provide automatic and remote monitoring via our cloud system and client can have access of it for 24 hours.