Divers' reports of the condition of the ice piers in New Castle Harbor. 1995? 1. Pier construction. Each ice pier consists of a rock filled timber crib substructure and a cut stone superstructure with rubble fill. Piers are either rectangular in shape or six sided with one long dimension. The width of piers varies from 40 to 47 ft and the lengths vary from 70 to 91 ft. The timber crib consists of solid walls made up of timbers that are positioned horizontally and stacked one on top of the other, each one spiked to the one below. The approximate a cross section of the wall timbers is 8 inches thick by 18 inches high. At each comer, timbers on adjacent walls are notched together as a log cabin would be. To prevent walls from bulging, timber tie logs are notched into the wall at approximately 10 ft intervals on each course. The crib is filled with rubble stone ranging from 3 - 18 inches in diameter. A 5 ft wide timber sill for the cut one superstructure is constructed around the o side edge at the top of the timber crib. The superstructures consist of a perimeter wall with three to six courses of interlocking cut stones that are each approximately 2 ft high, 2 ft wide and 6 ft long. Alternate stones are placed with the long dimension perpendicular to the wall face to tie the cut stone wall into the rubble fill material. Courses of stones are dowelled together with 3 inch diameter steel pins. The interior is filled with rubble stone fill. The top of the pier is capped with cut paving stones that are approximately I ft thick, 2 ft wide and 6 to 9 ft long. Octagonal stone mooring anchors or bollards are positioned near the four outside comers of each structure at New Castle and at each end of the structure at Marcus Hook. The location and identification of piers are described by Figure I and Figure 2. 2. Structural Condition. The condition of each structure was assessed on the basis of information obtained by divers inspections of the substructures and visual inspections of the superstructures. Divers inspections of the substructure were conducted on four ice piers at Marcus Hook and five piers at New Castle. Piers that are within the shoreline or under docking facilities were not inspected by divers. The superstructure of each ice pier was observed from a survey boat. The structural condition of the ice piers ranges from failed to good condition. New Castle. The diver inspection report for Piers I through 5 (see Figure 2) is included in Appendix B. Results for the divers inspection are summarized on Figure 4. The inland piers were not inspected by divers and could only be observed from a distance during the visual inspection. (1) Pier 1 [Pier K on 1879 report]. The river bottom is 22 to 28 ft below the top of the crib. The top 8 ft of the east face of the crib is deteriorated and has failed. Essentially the top 3 ft of the remainder of the crib is deteriorated or displaced. Several of the comers have separated. The entire east side of the superstructure and rubble fill material has fallen into the river. (2) Pier 2 [Pier M]. The river bottom is 22 to 24 ft below the top of the crib. The west, east and northwest timber walls have each buckled or bulged by approximately 3 ft outward between 10 and 20 ft below the top of the crib. Each comer has significant deterioration or separations. Several wall stones near the south nose are displaced and several stones along the southeast face are missing. The southeast bollard is leaning and the top paving stones of the southeast portion of the structure have settled noticeably (up to approximately 6 inches). Rubble stone fill material has accumulated on the river bottom along the west and east sides of the structure. Several wall stones are located on the river bottom to the south of the south nose. (3) Pier 3 [Pier N]. The river bottom is 23 to 27 ft below the top of the crib. The top 3 ft of the crib west wall and the north walls are in poor condition, and each comer of the crib has gaps and holes for up to 10 ft below the top of the crib. On the river bottom, rubble fill material is scattered all around the structure and a wall stone is located to the south of the south nose. The stone superstructure is in generally good condition. However, several stones along the southeast wall and southwest walls are displaced, the southeast bollard is leaning, and a concrete repair exists on the south nose. (4) Pier 4 [Pier L]. The river bottom is 23 to 25 ft below the top of the crib. Each comer has holes or small gaps near the top of the crib structure and there is a wall stone on the river bottom just south of the south nose. The top 3 ft of the west wall of the crib is displaced outward and the A has settled inside of the wall. The superstructure is in good condition with the exception that there is a missing wall stone on the south nose and the top of the crib has settled noticeably. (5) Pier 5 [Pier I]. The river bottom is 2.5 to 17 ft below the top of the crib. The top course of timber (1.5 ft) of the crib is deteriorated all around. Along the east face, the top two courses (3 ft) are severely deteriorated or missing. The northeast and southeast comers of the timber crib are open. The entire east side of the superstructure has faded and wall stones, paving stones and fill stones have fallen to the river bottom. (6) Southern Inland Pier [?]. The pier appears to be in good condition with a few wall stones displaced along the top of the east face. (7) Northern Inland Pier [?]. The superstructure appears to be in good condition; however, the east face sags significantly indicating some deterioration or settlement of the crib foundation. 3. Cause of Failure. The primary cause of failure is due to deterioration of the timber crib members which has caused crushing, settlement, and buckling of the crib structure. In several cases, the displacement of wall stones and bombards might have been caused by forces exerted by anchored ships or barges. 4. Repair. New Castle Piers. Significant repair and rehabilitation measures are necessary to restore or maintain the integrity of each of these piers. Two of the piers have collapsed and the others have significant issues regarding the integrity of the substructure. (1) Pier I and Pier 5. These piers have partially collapsed and essentially require reconstruction of a significant portion of the structure. The upper portion of the timber crib must be replaced and much of the cut stone superstructure must be reassembled. Plan sheets I and 2 describe the selected repair for pier 5 (Repair of Pier I would be similar.). The repair consists of the following: 1. retrieval and storage of wall and paving stones from the river bottom 2. removal and storage of the existing superstructure 3. removal of the deteriorated portion of the timber crib substructure 4. replacement of the removed portion of the timber crib walls with a concrete wall 5. replace inner rubble fill 6. re-assembly of the superstructure 7. repair of the comers. The comer repair consists of fabricating a steel stay in place form (using H-piles and a steel plate) that is filled with concrete to cap the opened comer. (2) Pier 2. Several (3 to 5) wall stones must be retrieved from the river bottom at the south end of the structure. To prevent further bulging of the walls and opening of the comers, the entire crib must be stabilized. The selected method to stabilize the crib is to contain the crib structure with a filled sheet pile cell structure as shown by Figure 6. A sheet pile wall would be constructed around the perimeter of the structure at approximately I to 2 ft from the existing walls. The void between the existing structure and sheet pile cell wall would then be filled with rubble stone fill. Prior to construction of the sheet pile wall, all voids would be fined with concrete. With the crib stabilized the stones along the southern walls of the superstructure should be re-positioned and the retrieved stones placed in correct position. (2) Pier 3. Each comer of the timber crib requires repair. Approximately half of the top portion of the crib wall is in fair to poor condition. The selected repair is the sheet pile cell repair described for Pier 2. This would stabilize the comers and contain any further deterioration of the crib walls. At least one wall stone must be retrieved from the river bottom at the south end of the structure. At the south nose, several (up to 10) superstructure wall stones should be repositioned and the southeast bollard should be re-positioned. An alternative plan for Pier 3 would be to repair the comers (as described for piers I and 5) and stabilize the walls in the future. A sufficient program to monitor wall condition would be necessary, (3) Pier 4. The west wall needs to be stabilized, and several comers require repairs. The selected method of repair is described in Figure 7. To stabilize the west wall, utilize a sheet pile wall the same as the sheet pile cell wall as described for Pier 2. The sheet pile wall would be positioned I to 2 ft from the existing west wall and would be anchored to the crib structure with H-pfles. Stone fill would be placed between the sheet pile wall and crib wall. The north and south comers require the Pier 5 comer repair shown on plan sheet 2. The holes located at the top of the northeast and southeast comers should be filled with concrete. (4) Inland Piers. The inland piers likely require substructure stabilization similar to the sheet pile wall repair described above. 5. Cost Estimate. 6. Recommended Action.