23 April 2018
Below part of the incident report on the Liebherr LR1300 crawler Crane, that overturned in Manhattan, killing one pedestrian and injured three others on the 5th of Feb. 2016.
1.0 Executive Summary
A Liebherr LR 1300 crawler crane collapsed at 60 Hudson Street in downtown Manhattan around 8:25 am EST on February 5, 2016. The crane fell in a south easterly direction on Worth Street.
The collapse resulted in one fatality, three injured pedestrians, damaged buildings on the northeast corner of Church and Worth Streets and damaged cars parked on Worth Street. The crane had a 194 feet main boom and a 371 feet luffing jib for a total boom/jib length of 565 feet.This configuration was included in the DOB approved drawings and confirmed by inspection.
A crane accident of this magnitude is normally a result of a combination of action / inactions / errors that occur over a period of time, and this is true for this accident. CTS concludes that theoperator failed to follow DOB regulations and the manufacturer’s requirement to secure the craneovernight on February 4th in advance of a forecasted wind/weather event.
On the morning of February 5th, the operator continued his improper actions by lowering the main boom to a 72° angle which put the crane at its stability limit. These compounded errors ultimately led the crane to collapse.The National Weather Service for Manhattan issued a Winter Weather Advisory Thursday afternoon (at 4:09 p.m. on February 4, 2016) for snow into Friday Morning that included a wind forecast of gusts up to 30 mph, and later increased to 35 mph at 8:56 p.m. that evening.
The morning of February 5 there was a noticeable increase in wind speeds between 5:00 am and 9:00 am with the prevailing wind direction from the north and north east.New York City DOB regulations require the operator to understand and follow the manufacturer’srecommendations (BC 3301.1.3), and to secure the boom when leaving the site (1 RCNY §3319- 01(p)(2)(vi).
The operator’s manual located in the cab covered requirements the operator shouldfollow in case of wind/weather related events and leaving the machine unattended overnight. When shutting down and leaving the machine overnight, the manual required the operator to place the boom and jib on the ground.
Further, the manufacturer required that the crane be placed in the“parked” position” prior to wind speeds reaching the speed at which no work is allowed (out-of-service wind). For this crane’s configuration (194 feet main, 371 feet jib), the wind speed was 7 meters per second (15.66 mph), and the “parked” position per the manufacturer was to “Lay down the boom and jib”.
The measurement of the unspooled boom and luffing jib hoist ropes show that the boom was at approximately 72° and the luffing jib at approximately 49° at the time of the collapse. The aboveangles are supported by the data retrieved from the crane’s computer and contrary to theoperator’s belief that the boom was 80° and the luffing jib at 45°.
The evidence did not show any structural or mechanical failures of the crane or its components. In addition, the foundation structure (cribbing) was within acceptable tolerances.
Watch the video below:
And the last part of the report reads:
5.7 Analysis of operator’s actions based on New York City Building Code
The code covers the requirements of all Hoisting Machine Operations. Below are specific instances that the operator violated code and the reason.
NYC BC 3301.1.3 requires that all equipment shall be used in accordance with the specifications of the manufacturer. The operator did not follow the specific instructions contained in the manual for stowing the crane overnight or when wind speeds wereexpected to exceed the manufacturer’s parked position speed.
1 RCNY 3319-01(p)(2)(x) requires operator to familiarize himself with the equipment. The operator lowered the boom to an angle lower than 72° and thereby making the crane unstable and then it collapsed. The operator experienced difficulty raising the boom Wednesday when he said that he needed to be at 76° to start raising the luffing jib.
1 RCNY 3319-01(p)(2)(x) requires operator to familiarize himself with the equipment. Theoperator’s manual in the cab clearly requires the operator to lay the boom down whenleaving the machine for a long work interruption that the manufacturer defines as overnight or one or more days.
1 RCNY 3319-01(p)(2)(x) requires the operator to familiarize himself with the equipment.The operator’s manual in the cab clearly says that the crane must be in the “parked”position when the allowable speed is exceeded or forecasted to be exceeded. For theconfiguration of 194 feet main boom and 371 feet luffing jib, the “parked” position is to lay the boom down. The operator clearly did not follow the manufacturer’s requirements.
1 RCNY 3319-01(p)(2)(x) requires the operator to familiarize himself with the equipment. He did not fully understand the manual where Table 3.2.1 shows the wind speed the crane can work and the required load chart reductions for the various wind speeds. The last column applies to the collapsed crane. For this configuration, operation is prohibited above 7 m/s (15.66 mph) and the boom should have been laid down.
1 RCNY 3319-01(p)(2)(vi) requires the operator to lower the boom to the ground or secure itagainstdisplacementbywindloadsorotherexternalforces. Theoperatordidnotlower the boom or secure it against displacement.
1 RCNY 3319-01(p)(2)(iii) requires the operator shall be responsible for the operation of the crane. The computer based load chart would not allow the crane to pick the two heaviest loads so the operator switched the computer to simulate the crane operating in two-part line while being in single part.
BC3319.6.3 requires the certificate of on-site inspection is valid only if the conditions and statements contained in the approved applications are complied with and the crane is operated in conformance with the provisions. On Wednesday, the operator elected to jack- knife the crane toward West Broadway which is 180° from the direction called for in the drawings provided by the professional engineer (MRA Engineering).
1 RCNY 3319-01(p)(2)(iii) requires operator to familiarize himself with the equipment. He did not use the proper technique to block the tracks. The manual in the cab did not containthis procedure so he should not have “blocked” the tracks. Further, the serialized manualrequires the use of steel plate with a thickness of 25 mm with precise placement and he used 3 sheets of 3⁄4 inch plywood (2.25 inches).
1 RCNY 3319-01(p)(2)(iii) requires the operator shall be responsible for the operation of the crane. He witnessed snow on the boom but failed to consider when lowering the boom.
BC3319.6.3 requires the certificate of on-site inspection is valid only if the conditions and statements contained in the approved applications are complied with and the crane is operated in conformance with the provisions. The engineer included a drawing that required the operator to stow the crane (jack-knife) in severe weather conditions as per manufacturer recommended procedures. There was a site meeting Thursday afternoon confirmed by two other site personnel that discussed the approaching storm. One of these persons said the gusts of 30 miles per hour were expected.
To calculate the boom and luffing jib angles at the time of the collapse, CTS used the length of the unspooled rope, the component weights and CGs from MRA’s ground bearing pressure calculation, and wind areas from Liebherr’s stability calculation. The results were that the boom was at 73° and the jib at 51°, and the crane would likely overturn in a 26 mph wind blowing from behind the crane, taking wind speed as uniform over the height of the crane. The boom and luffing jib angles change to 72° and 49°, respectively, when calculating the effects of elongation of suspension pendant bars and the boom and luffing jib ropes. In this position, the crane would likely overturn in a 4 mph wind blowing from behind the crane, taking wind speed as uniform over the height of the crane at these angles.
The evidence proves that the operator caused the collapse by not following the manufacturer’s recommendation that the boom be lowered to the ground prior to the wind exceeding 15.66 mph, not responding appropriately to a wind event, and lowering the main boom to our calculated 72° and the luffing jib to our calculated 49° angle prior to the collapse.
Further, CTS reviewed the reports and documents mentioned above and concludes that the operator’s failure to lower the boom and luffing jib to the ground the night before the collapse(February 4) is the primary cause of the collapse. This error was compounded by the operator lowering the boom to 72° and the luffing jib to 49° angle placed the crane at its stability limit. These compounded errors ultimately led the crane to collapse.
CTS holds this opinion to a reasonable degree of certainty, based upon the information reviewed and available to it at the time of writing. CTS reserves the right to review and possibly modify its findings should new information become available. SOURCE: NYC