ÇATALHÖYÜK 1999 ARCHIVE REPORT

Shelter and Shoring Construction

Korunak Ve Destek Yapımı

Lindsay Falck

Abstract

The three main on-site construction projects were the construction of a large shade roof over the South Area, the construction of a shelter over the North Area to allow building 5 to be put on public display and the construction of a shoring system for the deep excavations of the South Area.

Özeti

Alanda yer alan üç konstrüksiyon projesi: Güney Alanı’daki geniş gölgeliğin yapımı, Kuzey alanı Bina 5’in sergiye açılması çalışmaları sırasında yapılan korunak ve Güney Alanı’daki derin sondaja yapılan destekler.

The three main on-site construction projects for the 1999 extended dig season were the construction of a large shade roof over the South dig site, the construction of the on-site museum and display area of the North site, Building 5, area, and the construction of the shoring system for the deep excavations of the South site.

The design of the South site shade roof and shoring was undertaken by Lindsay Falck with assistance from the ARUP engineering office of Istanbul, Baran Özsöy being the project designer. The design of the North site display shelter was by Lindsay Falck with detail design by Caitlin Moore, David Small and Paul Lapinski.

All this work had to be done on an extremely tight construction budget.

South Site Shade Roof

Lindsay Falck visited the site and made accurate measured drawings of the current ground configuration of the dig site with major assistance from Atakan Güven, who did all the survey instrument work, during the period 23 April to 30 April.

The first ideas for the roof were to use local steel bar-joist trusses and canvas for the covering. This system was designed with help from ARUP Istanbul and London but, when sponsorship could not be found to fund the structure, a second design using poplar-pole trusses was made with much shorter clear spans. Insurmountable problems with this system resulted in the final proposal, using a light-weight, tension-cable, net structure with a canvas covering.

The cable-net-systems allowed for two lines of poplar-pole support-columns to be placed very lightly on the archaeological surfaces, using wood spreader plates. Sandbags were loaded onto these spreader plates to create down-force loads to resist wind uplift forces on the roof membrane.

Very light steel cables were strung across the support columns at 3-metre intervals and secured at their ends, well clear of vulnerable surfaces, with steel pin-and-spade anchorages. A cross grid of support wires at one metre centres in one direction and 1.5 metres spacing in the other direction supports the canvas roof panels. These canvas panels were loose-laid over the cable net and secured to separate anchorages with bungee chords, to allow the wind to pass through the panels under severe wind conditions. This avoided the serious problems of having to provide excessive hold-down forces on the delicate archaeological surfaces.

All materials were brought locally in Konya or Çumra and assembled on the verandah of the dig building by Lindsay Falck, Ismail Yaslı and Hasan Tokyağsun. On-site assembly was a marvellous whole-team effort with most of the archaeologists and Turkish workers helping with the threading of cables, etc. Khan, Shahina, Adnan and John and others helped with completion of the work after Lindsay returned to America.

The final design and construction phase for this work was in the last week of May and the first week of June.

The roof is a very simple mono-pitch, sloping upwards from North to South so that prevailing winds from the North ventilate the excavation by pulling the layer of warm air from under the roof and outwards thereby greatly reducing working temperatures in the dig area. The canvas, being translucent, gives very high levels of neutral-colour lighting in the work areas below the roof. Canvas side-skirts cut off the very low East and West sun angles in early morning and afternoon periods. The bungee chord system for securing the canvas panels works well in that in light wind they resist upward flapping movement of the canvas but in gusting wind conditions all the wind to "leak" through the overlapping joints of the canvas roof surface.

A very big "thank you" to all those who gave this project so much moral and physical support. A great party was held on the night before Lindsay’s return to America in early June.

Shoring to the South Site "deep-dig" area.

Baran Özsöy of the ARUP Istanbul office designed the heavy shoring system for the approximately 10-12 meter deep "deep sounding" excavation during May and visited the site to check site conditions. A prototype test piece of this design was made and set up during the end-of-May visit by Lindsay Falck. During June, Shahina and the team inserted the first four sets of steel prop and wood lagging systems in the uppermost level of the dig site. The second, deeper set of lateral props was set in position in mid-August, by Lindsay Falck, Paul Lapinski, David Small, Caitlin Moore, Anwen Cooper, Duncan Garrow, the Turkish workers and others just prior to the final phase of excavation to the deepest level being commenced. Two longitudinal shoring props were also inserted during this final dig stage.

The whole shoring operation was an extremely difficult one but critical to the life-safety of the archaeologists who undertook the deep sounding excavation work.

Although Çatalhöyük is in a very low intensity seismic zone of Turkey, earthquake movement could cause severe lateral forces to develop in the mud-brick and midden walls of the site excavation. With one team member’s ever present memory of an archaeologist’s loss of life adjacent to him in a dig-site in Palestine, everyone was well aware of the critical importance of the safety of the shoring system for this very deep excavation. To reduce the risk of accidents in the handling of the very heavy steel tube props and cross head beams in the dig area, the system was modified by making the cross heads removable. This made it possible to trim the wall surfaces very accurately, ensuring a very tight fit for the wood lagging boards.

The resultant work was of a very high standard thanks to the exacting standards set by Paul, Ismail, David, Caitlin, Adnan and all the others who did this very taxing work.

North Shelter - Building 5 Museum

With budget-restrictions being so tight, it was decided to adapt a locally made, ultra light steel portal frame structural system for this building. A local steel erection firm in Cumra makes these structures for local tomato growers. Initial discussions with this firm met with great enthusiasm for them to do this work and this spirit of good will and very high standards of work ran right through this project.

Lindsay Falck produced the overall design for the building in Philadelphia during June and came back to Çatalhöyük in mid-August with Franck Matero and Caitlin Moore to oversee the later stages of construction and to develop the detail design of the footbridge, floor, etc.

The design developed into a simple she-shaped double skin tent with convection-induced ventilation between the inner lining and outer tent-skin exiting through a slot in roof apex, facing in the direction of the local prevailing winds. The plan provided for a large wood floored display area and a viewing bridge across the dig area. Paul Lapinski and Davis Small started the construction process, were joined midway by Lindsay and Caitlin. Caitlin did all the detailed construction drawings and the whole project was brought to a successful close by Davis Small who delayed several flights to complete the work. Franck Matero did all the final negotiations with the tent makers, carpenters for the floor and iron workers for the bridge. A huge thanks to all concerned with this on-site work. The steel-frame from Cumra deserve special praise for their major contribution.

A very special thanks to ARUP of Istanbul and ARUP of London who gave their consultant expertise to the Çatalhöyük project on a Pro Bono, no charge basis. Baran and Hamdi of Istanbul and Chris Wise of London deserve special thanks in this connection.

Endurance medals go to Shahina for the unruffled problem solving on site and to Ian for steering us through the financial rapids.

A great set of projects with a marvellous team.