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2018-03-04

Ester Tower in Jerusalem, Israel

A timber lookout tower called "Ester" opened in Jerusalem in mid-November 2017. This tower, designed in the shape of a cactus by renowned Czech architect Martin Rajniš, is located in the complex of a former hospital from 1887, not far from the old town walls ...

All timber, steel, and membrane elements were prefabricated in the Czech Republic and then loaded into two containers with a length of 12 m (37 ft) each. All components were manufactured to a high quality, both manually and using CNC technology. This quality standard was an essential prerequisite for the successful and quick assembly in Israel.

All the prefabricated components were assembled in a horizontal position, including the spiral stairway inside the wooden supporting cuboid.

Structure

The tower is anchored to the reinforced concrete foundation slab supported by four piles, each with a diameter of 35 cm (14 in) and a length of 7 m (23 ft), bored mainly in rocky subsoil. The lookout tower consists of two main mutually acting structural systems. The load-bearing main core with a height of 12 m (39.4 ft) is formed by four load-bearing main timber columns (28×28 cm / 11×11 in – GL28h), which are set up at a center distance of 2.3 m (7.5 ft).

The basic framework is followed by the second structural system, forming the external shape of the tower. The cactus shape is achieved with an octagonal prism. All structural components are designed in a way so that it is possible to replace them with a new component at any time.

Above the viewing platform, the facade structure ends with a dome with a central steel ring gathering eight steel beams. The roof structure is designed in combination with the hot-dipped galvanized steel supporting frame and a special membrane made of ETFE foil. The designers have excellent experience with these membranes from the project of the “Gulliver” airship for the Center for Contemporary Art in Prague.

The Czech-Israeli project by architect Martin Rajniš in the magical city of Jerusalem can serve as a symbolic expression of the traditionally good relations between the two countries.

Location Gdalyahu Alon St 14, Jerusalem, Israel
Structural Analysis TIMBER DESIGN s.r.o.
Ing. Zbyněk Šrůtek (Timber, Steel, ETFE Membrane)
Česká Skalice, Czech Republic
www.timberdesign.cz

Prof. Dipl.-Ing. Michal Bar Ilan (Foundations)
Israel
Architects Prof. Ing. arch. Martin Rajniš, Ing. arch. Tomáš Kosnar
Prague, Czech Republic
hutarchitektury.cz
Main Contractors Huť architektury Martin Rajniš s.r.o.
Prague, Czech Republic
hutarchitektury.cz

TIMBER DESIGN s.r.o.
Česká Skalice, Czech Republic
www.timberdesign.cz

Maik Engineers Ltd.
Israel


Project Specifications

Model Data

Number of Nodes 818
Number of Lines 1442
Number of Members 1434
Number of Surfaces 0
Number of Solids 0
Number of Load Cases 15
Number of Load Combinations 0
Number of Result Combinations 0
Total Weight 10.631 tons
Dimensions (Metric) 7,414 x 15,908 x 7,414 m
Dimensions (Imperial) 24.32 x 52.19 x 24.32 feet

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