Barrette Foundations — Two Case Histories from Turkey

In the recent decades construction of tower structures in big cities around the world is a new trend that has been followed. As a result, engineers are faced with foundations to be designed and constructed under heavier super structural loads imposed by such structures. Often, poor subsoil conditions, site heterogeneity, variability in geometry, and high seismicity brings further challenge in cost effective and safe foundation design. To overcome such complexities and meet higher load capacity requirements often barrette foundations have been utilized instead of cast in situ circular large diameter piles. In this paper applications of barrette foundations together with the emphasis on key issues controlling their design and construction are presented using two recent case histories from Turkey. The first case history, is a covered sports arena with a capacity of 18,000 thousand people and is constructed at the Asian part of Istanbul. Main lithological units underlying the site are the upper uncontrolled fill of variable thickness and underlying bedrock. The second case history is Folkart Towers, Europe’s 5th highest twin towers project in Izmir presently under construction. Subsoil conditions at the site is very poor with alternating layers of alluvium consisting of gravel, sand, silt and clay layers with very high groundwater table. Both sites have very high past seismic activity. In the first case, foundations are designed and constructed by means of socketed barrettes into the underlying bedrock. The design loads of barrettes considering only skin resistance along the socket are estimated using empirical equations proposed by various authors in the past. In the second case, both skin resistances and tip resistance developed are estimated using mechanical modeling of subsoils determined as a result of soil characterization by means of in situ measurements using similar procedures utilized in circular pile design. In both cases, estimated capacities are checked at the design stage by means of O’Cell load testing performed on constructed barrettes at a representative location of the site in order to end up with safe and economical foundation design. Verticality and constructability of barrettes having long lengths are another key issues to be considered during design and construction. Instrumentation and monitoring techniques that could be utilized to ensure verticality are also presented within Folkart twin towers project

Assessment of Liquefaction/Cyclic Failure Potential of Alluvial Deposits on the Eastern Coast of Cyprus

The main objective of this paper is to evaluate liquefaction potential and cyclic failure of subsoils of Tuzla area located on the eastern coast of Cyprus. The in-situ tests of cone penetration test (CPT) and standard penetration test (SPT) were used for site specific evaluation of liquefaction potential. Index properties and undrained shear strength (su) were used to assess cyclic failure potential of fine-grained soils. Liquefaction potential index (LPI) was evaluated based on the calculated factor of safeties for each CPT location. Sensitivity of soils was indirectly estimated from liquidity index (LI). The samples tested displayed high sensitivity values, indicating vulnerability to loss of strength and excess deformations during cyclic loading

A Case Study on the Use of Flexible Earth Retaining Structure In Instable Slopes

Recently new highway, motorway and railway projects take place in many developing countries within the aggressive infrastructure investment programme of governments. In rugged topography, engineers face the challenging problems of designing safe and cost effective cuts and fills for these projects especially under seismic loading and marginal stability conditions. Overall stability mechanism and safety of the cut generally controls the design decisions for the relevant section. In addition, because of the construction width limitations, in some mechanically stabilized earth wall projects sufficient width to accommodate the strip lengths of the retaining system cannot be provided. To eliminate all these problems, to minimize cut and backfill volumes and provide an innovative solution in such difficult terrains, soil nailing is implemented in the cut side together with the mechanically stabilized earth wall in the fill side together both are being flexible earth retaining structures. In addition, soil nails could be designed in such configuration and length that nails will also contribute to overall stability conditions of the cut slope. Furthermore, implementation of the system brings the advantage of reduction of both cut and fills volumes, therefore more cost effective and safer design. This paper presents application of this system in a recent case study, in Baku, Azerbaijan

Static penetration resistance of soils

Model test results were used to define the failure mechanism associated with the static penetration resistance of cohesionless and low-cohesion soils. Knowledge of this mechanism has permitted the development of a new analytical method for calculating the ultimate penetration resistance which explicitly accounts for penetrometer base apex angle and roughness, soil friction angle, and the ratio of penetration depth to base width. Curves relating the bearing capacity factors to the soil friction angle are presented for failure in general shear. Strength parameters and penetrometer interaction properties of a fine sand were determined and used as the basis for prediction of the penetration resistance encountered by wedge, cone, and flat-ended penetrometers of different surface roughness using the proposed analytical method. Because of the close agreement between predicted values and values measured in laboratory tests, it appears possible to deduce in-situ soil strength parameters and their variation with depth from the results of static penetration tests

Harmony of Retaining Systems to Various Local Subsoil Conditions – A Case Study

A case study for the utilization of various retaining systems for different subsoil and groundwater conditions encountered within a given site is presented in this paper. The project is known as “BJK Fulya Complex”, covering approximately 160,000 m2 floor area. It is located at a very prestigious district of the city, therefore maximum underground space gain were desired. As a result nearly 20 m of excavation is planned to be performed partly under groundwater. Due to unique topography and geology of the site, subsoil and groundwater conditions at various faces of the excavation differ considerably. Because of the complicated geology, budget constraints of the project and the high seismicity, it was compulsory to employ various retaining structures such as flexible and rigid retaining systems at various locations within the site including permanent and temporary soil nailing, permanent tie-back cast in-situ reinforced concrete wall and temporary tied-back diaphragm wall consist of soldier cast in-situ piles with jet grout columns in between. Performances of various systems are monitored closely by means of inclinometers. Displacement data and experience obtained from this case study serves an excellent source of data and example for future applications in similar conditions within the city

Comparison of Dynamic Soil Modelling Using SCPT, SDMT and SASW

A site investigation campaign using cone penetration test (CPT), dilatometer test (DMT) are carried on alluvial deposits at a site located at Gemlik, Turkey towards the design of a newly planned hot reverse mill structure within the existing Borçelik steel factory. Site is located at the south of North Anatolian Fault that is sheared during 1999 Kocaeli Earthquake. In addition, the site is under the influence zone of another fault line going through the Gemlik Bay. Therefore, prediction of the behaviour of saturated alluvial deposits under a major expected design earthquake of the planned structures is the prime importance in terms of safety and meeting the performance criteria of the subject structures. Seismic cones (SCPT) and dilatometers (SDMT) together with spectral analysis of surface waves (SASW) are also carried out in order to obtain shear wave velocity profile for seismic modelling. Data obtain from CPT, DMT, SCPT, SDMT and SASW is used for subsoil geotechnical modeling. Soil models are also supported with SPT data and laboratory test results. Obtained Vs profiles with various techniques are compared for whole site models and between closely located investigation pairs

Case History of Osterberg Cell Testing of a Φ1500mm Bored Pile and the Interpretation of the Strain Measurements for Princess Tower, Dubai, U.A.E.

This paper reports a well-documented case history of a successful Osterberg Cell testing performed on a working pile cast for the foundations of the Princess Tower in Dubai. Princess Tower which is considered as the tallest residential tower in the world (currently being registered with Guiness Book & Records) up to an approximate 5000 tons demonstrating the efficiency of the testing methodology when accompanied by high-quality construction technique. The tower is 107 floors high and contains a combination of luxury apartments, offices, sales outlets, car parking spaces, sports and recreational clubs and hotel suites. The Osterberg load test was carried out on a pile referred as P34 on October 22, 2006. The main objective of this load test was to proof-load the test pile to its maximum test load of 4,950 tons which is 1.5 times the safe working load of 3,300 tons. For this purpose 3x900 tons capacity hydraulic jacks were utilized. The test pile was a 1,500 mm diameter bored pile with a total embedded length of 47.6m below the cut-off level. Eight levels of vibrating wire-type strain gauges comprising three units at each level were also installed on the test pile to measure strains at nominated locations. According to settlement values and the satisfactory cross hole sonic logging results, it was concluded that the tested pile can safely carry the design working load in compression with settlements within the allowable limits

An Improved Methodology for Estimating Future Reservoir Storage Capacities: Application to Surface Water Supply Reservoirs in Illinois (Second Edition)

published or submitted for publicationis peer reviewedOpe

Optimal Use of the Kaskaskia Navigation Canal: Management Strategies and Guidelines

published or submitted for publicationis peer reviewedOpe

Lunar surface engineering properties experiment definition. Volume 1: Mechanics, properties, and stabilization of lunar soils

Lunar soil simulation and stabilization, and impact penetrometer studie