Installation of the Kilauea Jacket and Piles and Full-Scale Validation of Analyti'cal Predictions
Authors: Serpas R.J. , Chandra T.K. , Popp D.D. , Sircar S. 
Published: October 2008

The installation of the Kilauea jacket in 622' water depth took place from July 9 through July 25, 1989. The jacket installation, including the transportation, launch, self-upend, set down, pile installation, and grouting, is presented. Planning of the installation and a narrative of the actual operations are described. Variations between the planned and actual installation operations are discussed and a comparison of the analytical predictions and full-scale observations made during the actual installation operations is addressed.

The paper demonstrates the reliability of currently-used analytical predictions for jacket behavior during installation.

JACKET TRANSPORTATION

Tow Route

The transportation of the jacket to the launch site consisted of two phases. The 39 mile river tow phase covered the tow from the load out site at Amelia, Louisiana, through Bayou Chene and the Atchafalaya River to Eugene Island Block 140. The 75 mile Gulf tow phase commenced at that point and continued to the launch site. This tow route is shown in Figure 1. The launch barge Intermac 650 (I-650) was used to transport the jacket.

Planning

The river tow required passage through shallow water and a number of turns. This required a shallow draft. Since environmental conditions were not a concern in the river tow, low horsepower, maneuverable tugs were used. The tow plan called for trailing tugs to control the tow at the low speeds and assist in the curve negotiation. The trailing tugs used the launch rigging to minimize rigging at the top of the jacket. The river tow configuration and barge ballast plan is shown in Figure 2. The ballast plan provided for a 14'-9" draft at the stern and a 14'-7" draft at the bow with maximum barge deflection less than 2". Please refer to Reference 1 for a discussion of the barge deflection limitations. Planning called for the river tow to reach the Gulf during daylight to facilitate rigging for the Gulf tow.

The Gulf tow required more draft to reduce jacket member stresses under tow design environmental conditions. A stepped ballasting procedure was developed to change drafts while keeping barge deflections within allowable limits (less than 2"). Since barge deflections would not be monitored during tow, analytical methods similar to those used to predict barge deflections during load out were used to develop the stepped ballast procedure. The adequacy of this analytical method had been confirmed during load out operations and subsequent draft-change operations (see Reference 1). For the Gulf tow, the tow plan called for three 3600 H.P. leading tugs with no trailing tugs. This tow configuration and barge ballast plan is shown in Figure 2. The ballast plan provided a 24' draft. The tow was expected to take approximately 18 hours.

Since the deeper Gulf-tow draft was only required if adverse environmental conditions were expected, the tow plan allowed ballasting during the tow if favorable weather conditions were forecast. This allowed the tow to take advantage of good weather conditions and minimize jacket exposure during the time between the commencement of the Gulf tow and launch.