part 1. technical report structure

8/12/2019 Part 1. Technical Report Structure

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Site Location

Flo Cafe is placed on the site of approximately 245m2 in the very centre of the

city of Misurata ( 3222'22.74"N - 15 5'24.98"E ). The site is opened from the

south-east side to the street and it is widely opened to the public park area

across the street, about 4000 m away from the Mediterranean Sea.

Climatic data

Data is obtained from synoptic weather station at the Tripoli International

Airport over the course of an average year. It is based on the historical records

from 1974 to 2012. Earlier records are either unavailable or unreliable.

Temperature

Misurata has a hotsubtropicalsemi-arid climate with long, hot and dry

summers with relatively wet and mild winters with aMediterranean (dry-

summer) rainfall pattern. Summers are hot with temperatures that oftenexceed 38C.Average temperatures in July are between 22 and 33 . The

record high temperature is recorded as 48C in August. In December,

temperatures have reached as low as 0 , but the average remains between 9

and 18 C.

In conclusion, the temperature range from 0 to +48C is assumed for design.

Rainfall

The average annual rainfall is less than 400 millimetres, and can be very erratic.

Wind Speed and Direction

Wind is the dominant lateral load for this type of structures.

According to the work Wind Load Characteristics in Libya(2010) by Prof.

Milad M. Alshebani (the Department of Civil Engineering Alfateh University,

Tripoli) and Mohammed B. Abohedma (postgraduate of Civil Engineering

Department, Alfateh University, Tripoli), Libya is affected by atmospheric

depressions during the winter time and north-eastern trade winds in the

summer. Libya is also exposed to Ghibli " winds, a dry and hot windthat blows

from the south several times per year, usually from late spring throughout

summer season.

Over the course of the year, typical wind speed varies from 0 m/s to 8

m/s (calm to fresh breeze), rarely exceeding 12 m/s (strong breeze).

The highestaverage wind speed of 5m/s (gentle breeze) occurs around May

30. At that time, the average daily maximum wind speed is 8 m/s (fresh

breeze). The lowestaverage wind speed of 3 m/s (light breeze) occurs

around first week of December. At that time the average daily maximum wind

speed is 6 m/s (moderate breeze).

In Libya, measurement of the wind speed is based on 10-sec gusts wind speed.The most frequent wind speed is 15 m/s. After examining wind speeds and its

frequent durations, it has been envisioned that Libya can be classified into four
http://en.wikipedia.org/wiki/Subtropicalhttp://en.wikipedia.org/wiki/Semi-arid_climatehttp://en.wikipedia.org/wiki/Mediterranean_climatehttp://en.wikipedia.org/wiki/Celsiushttp://en.wikipedia.org/wiki/Celsiushttp://en.wikipedia.org/wiki/Mediterranean_climatehttp://en.wikipedia.org/wiki/Semi-arid_climatehttp://en.wikipedia.org/wiki/Subtropical


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wind speed zones in ascending order of its annual maxima wind speed.

According to this classification, Misurata is placed at Zone 4, with the design

wind speed of 121 km/h (33.6 m/s), a return period of 50 years.

In conclusion, a basic wind speed of 33.6 m/s is assumed for the design.

Geological constraints

According to the article Settlement of a Building Founded on Difficult Soilwritten by Iqbal H. Khan, Associate Professor and Fathi M. Layas, Lecturer,

Department of CMI Engineering, University of Garyounis, Benghazi, Libya, and

Road Construction on Sabkha Soils, written by Mohamed Mehemmed

Shahin Department of Civil Engineering, 7th October University, Misurata, Libya,

the large areas in Libya have Sabkha soils, which is an Arabic expression for

describing recent coastal sediments with a high salt content are characterized

by very low bearing capacities and a relatively hard crusty surface which is

strong when it is dry and loses its strength upon wetting. It forms heterogeneous

and complex soil profiles with poor mechanical properties and appreciableorganic. Sabkha is composed of sand deposits mixed withsilt and clay. Two

types of Sabkha are present in Libya, the first one is the coastal or muddy

Sabkhas, which is found along the Mediterranean Sea, and the second type is

inland or Sandy Sabkhas, which is located in the southern part of the country.

Clearly, the muddy Sabkhas, which is potentially the soil under the actual

structure, are the worst to construct structure on it. The main geotechnical

hazards include settlement, corrosive action, heave due to salt crystallization /

recrystallization and flooding due to the low infiltration rates. A site

geotechnical investigation has not been undertaken yet. In order to design

stabile and proper foundationsfor the building, it is highly recommended thatsuch investigation should be carried out by the Client.

Seismic constraints

Seismic History

From work undertaken by A. Suleiman et al, of Al Fatah University, it is known

that the Hun Graben area (western part of the Gulf of Sirt), with the prominent

rift valley between Han and the city of Al Qaddahiya, has been identified as

the location of many historic earthquakes. This includes the major quake, near

Al Qaddahiya, in 1935 which was registered as a magnitude of 7.1 on theRichter scale, with two aftershocks of 6.4 and 6.0. A further quake hit the same

area measuring 5.6, in 1941. Also, in Tripoli a major earthquake occurred in

1183 AD, destroying the city. Likewise, mild tremors were felt here in 1803, 1811

and 1903.

Therefore, it can be assumed that the site lies in an area that is historically at

risk from severe seismic effects. The buildings and structures should be classified

with regard to their importanceand designed and detailed to resist the

effects of earthquakes.

Determination of design parametersAccording to EN 1998: Euro code 8, the following parameters should

determinate detail calculation of structure forces: 1) Identification of ground


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type, which is the result of geotechnical investigation, 2) the value of the

reference peak ground acceleration on type A ground, agR, chosen by the

National Authorities for each seismic zone, corresponds to the reference return

period TNCR of the seismic action for the no-collapse requirement (or

equivalently the reference probability of geology in 50 years, PNCR) chosen by

the National Authorities. 3) Determination of the Design spectrum for elastic

analysis. To avoid explicit inelastic structural analysis in design, the capacity ofthe structure to dissipate energy, through mainly ductile behaviour of its

elements and/or other mechanisms is taken into account by performing an

elastic analysis based on a response spectrum reduced with respect to the

elastic one, henceforth called a "design spectrum". The seismic motion may

also be represented in terms of ground acceleration time-histories and related

quantities (velocity and displacement). Depending on the nature of the

application and on the available information, the description of the seismic

motion may be made by artificial accelerograms and recorded or simulated

accelerograms. The method which will be chosen depends on availability ofdata provided by the site investigation.

Conclusion

The seismic hazard of the site depend both on intensity of the ground motion

and also, the frequency of occurrence of the earthquakes represented by

seismic parameters which should be the result of the site geotechnical and

investigation and national recommendations and regulations.

Sub Structure

According to Geological constrains, the bearing capacity of the soil can vary

a lot, so after the Geotechnical investigation is carried out, it will be chosenthe appropriate type of sub structure. In this stage of design a strip foundations

under the walls of the concrete blocks are considered as adequate way to

transfer loads safely to the ground. But if geotechnical investigation results

show that the soil is too weak, an appropriate measures for strengthen the sub

soil will be carried out.

Super Structure

Structural system is concrete hollow blocks walls based on strip foundations

straighten with reinforced columns and ring beams in the first floor level. Firstfloor is two-way reinforced concrete slab supported by reinforced concrete

beams.

The roof is self-bearing vaulted steel panel.

The main faade wall is about 10 m high and 14 m wide in base. Structural

system of the wall is grid of the steel columns and beams welded together in

shop and site. The faade wall has to carry weight of the glass faade and

lateral wind force. Due to high speed of the wind, the intensity of the wind

load is significant which results with strong columns.

Structural Materials


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Structural material is concrete hollow blocks walls, reinforced in-situ cast

concrete and steel. Concrete quality should have fc=30 MPa (C 25/30

according to EN 206) or better. Reinforcement steel should have yield strength

fyk=360 MPa or better. Steel quality is S235 with minimum yield strength 235

MPa.

Structural DesignCalculation of structure forces was carried out on 3D model in order to

determine real behaviour of structure under the all possible combinations of

applied loads, vertical and lateral as well. Deflections of the structure were

calculated taking in the consideration creep and shrinkage of concrete

during the time of structure exploitation.

Structure resistance to lateral loads is achieved by stiffness of the reinforced

frames in two orthogonal directions.

Vertical Loads on Structure

Vertical loads are Self-weight of structure, Dead and Live (Implied) load. Self-

weight is calculated by Program, Dead load are weight of the walls and floor

layers. Live load is variable load which intensity depends of use of areas. For

design is used vertical, uniformly distributed load of 3.0 KN/m2- restaurant area

(EN 1990-2001).

Durability

To achieve durability the following inter-related factors were considered in the

design:

the intended or foreseeable use of the structure the required design criteria

the expected environmental conditions

the composition, properties and performance of the materials and

products

the properties of the soil

the choice of the structural system

the shape of members and the structural detailing

the quality of workmanship, and the level of control


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part 1. technical report structure

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