Germany - shoring works

Description

The city of Herzogenaurach is realising the replacement of the town hall and the renovation of the castle building. Archaeological finds are to be expected in the course of the construction work. The soil and earth works are accompanied by an archaeologist. planning data: Constructed area New construction 1 794 m2, area Building plot: 6 704 m2, surface area Building pit: 1 720 m2, surrounding area Building pit: approx. 170 m, average ground height 300.60 m NN. Due to the inner-city location, there are requirements which must be complied with when carrying out the construction work (in particular BImSchG, AW Baulärm, BayDSchG). Work on Saturdays shall only be carried out in exceptional cases and with the prior written consent of the client. Downtimes due to archaeological work are possible. In the course of the archaeological work, a mini excavator/chain excavator and personnel are to be provided, manual excavations may be necessary. The services to be provided are special foundation work. The excavation pit must be secured by means of water-impermeable and back-anchored shoring, predominantly by means of an overlapped bored pile wall (reinforced pile diameter = 900 mm, pile length from 9 m to 11 m, total bore length approx. 2,500 m, overlap dimension 15 cm, empty bores up to 5.8 m required) incl. drilling template. In addition, a total of approx. 1,400 m of strand anchors (4-7 strands, 0.6'') are to be provided for the back anchoring of the excavation pit. 3 m of HDI underpinning with approx. 4-6 m long jet grout bodies (D = 100-120 cm) is to be provided in the area of the listed ring wall. Drilling in the groundwater is carried out with the aid of water ballast and the excavation pit is kept dry by means of closed dewatering (12 deep wells and 5 pump sumps). The amount of water produced per year is approx. 175 000 m3. The neighbouring buildings are to be recorded in advance by means of an evidence preservation procedure. Well drilling is carried out within the excavation pit with supported borehole walls in the groundwater, obstacles are to be expected (e.g. building remains, masonry, concrete, wood, steel, ...). The dewatering system is to be operated, monitored and maintained/documented, and the planned excavation level is 294.34 m above sea level. The excavation pit bottom is located at a height of 293.84 m above sea level, so that an approx. 50 cm thick protective layer remains. This protective layer is later excavated by the AN bodyshell. Approx. 9 700 m3 of soil material must be excavated and removed. (homogeneous areas I.A, I.B and I.C, gravel layer in the castle garden area). Of which to be disposed of:- second intake soil approx. 8 212 m3,- soil and stones approx. 14 530 tons (LAGA Z 0),- soil and stones approx. 1 560 tons (LAGA Z 1.1),- construction waste (AVV 170107, DK I acc. to DepV) approx. 21 tons, - backfilling material basement floor and castle ditch (gravel, mineral concrete) approx. 5,000 tons. the demolition work of the basement floor of the existing building in the excavation pit takes place under safety measures of the existing building / castle successively. In addition, demolition work is being carried out on the grounds of the castle courtyard. The demolition material must be disposed of properly. Earthworks must be carried out within the construction site. A safety drainage system is to be constructed (construction of a dam drainage system and shafts, underpinning of the sewage pipe, supply of underwater pumps as an emergency measure), the final documentation is to be prepared, vibration measurements are to be carried out for the duration of the special civil engineering measures, as are surveying services and declaration analyses.

Opportunity closing date

22 May 2019

Value of contract

to be confirmed