Structural design of a Massive housing unit in Colombo

 We did  the structural design of this massive housing unit to be built in Colombo. Structural modal was done using the csi etabs software. Below you can see the analyzed stresses on the slab elements of the building.

Below is the column layout drawing provided by us for the construction.

Below you can see the reinforcement drawing of the columns. It shows the reinforcement steel bar diameter and the diameter of the stirrups and spacing's as well. It also shows the the levels and the existence of the column at each level.

Below you can see the structural modal with the proposed element sizes at the initial design stage.

Structural Design for twin houses in Boralesgamuwa

This elegant twin luxury houses near Katuwawala, Boralesgamuwa was designed by MC&C Architects and the client was MG Homes.  The structural design was done by Chartered Structural Engineer, Isuru S. Amarasena.  Initially the the soil investigation was carried out and came to know that a little silty sandy soil was available under 3 feet of the existing ground level. According to the soil condition a little soil improvement was proposed and and carried out. 

These photos were taken during the construction stage. 

Below you can see the deformed shape of the building when the preferable loads applied on the structure. It clearly shows the deflected shapes and the structural engineer ensured maintaining the deflections in the allowable range in-order to provide a better serviceability requirements.

Below images shows the service loads acted on the foundation coming from through the columns from the superstructure above. By considering the existed soil condition and the provided soil improvements, structural engineer designed pad foundation sizes, reinforcements and the rubble foundation and tie beam system. These analysis for calculating the footing loads is essential for providing the economical footing sizes. It ensures the required additional strength for the heavily loaded footings and also it saves the clients money by choosing the small sizes and reinforcements for the slightly loaded footings.

Below image shows the axial forces acting on the columns of the house. The reinforcement requirement of the columns is governing by two factors, Axial forces and the bending moments. Structural engineer does the analysis for finding the governing factor for each column and selecting the required reinforcement by avoiding providing much larger reinforcements for all the columns.

Below diagram shows the bending moments induced in the beams. It is required to provide adequate reinforcement to withstand the acting larger moments in those relevant places in-order to avoid the cracks and deflections. and also in the column beam junctions the beams are required additional reinforcements for the top layer as they have more hogging moments. These things were well managed and the structural drawings were prepared by the structural engineer. It saved clients money and time and also ensured the required stability and strength of the structure.

Below you can see the stresses induced on the slabs.

When you have a house or building, in-order to avoid the settlements, cracks and to save your money and also in-order to ensure the stability of the structure please consult a professional chartered engineer and get done a structural analysis and have some structural drawings prior to the construction stage. Otherwise lot of problems may occur during and after the construction stage which will lead to huge money losses. Be wise and be happy. Thank You!

 

Elegant House Design at Pannipitiya

 This elegant house's architectural design is done by the architect, Chathura Perera. His designs have unique features but arranged in a simple grid system which leads for economical beam designs. If the house or building has simple square based continuous grid system it will be able to used parallel continuous equal span beams and they usually have smaller beam depths and minimum reinforcement areas which leads to lower the material and construction costs. Actually architecture is not a word for unique building elements which used a very difficult construction methods with a higher cost. It is a science of having the required utilities with a minimum cost and contains an elegant appearance. This thing is nicely handled by Architect Chathura Perera and Hats off for him and his designs. 
The house is constructed near pannipitiya and very close to Devram Viharaya. The Structural design is done by Chartered Structural Engineer, Isuru S. Amarasena. He is working as a Senior Design Engineer (Structural) in the Structural design section of Central Engineering Consultancy Bureau. 

The substructure is having some pad foundations with 3ftx3ft and 3.5ftx3.5ft sizes. All the foundations are connected with tie beams. The loose soil part was found during the excavation of foundations and it was filled and compacted with quarry dust for a better bearing capacity and to avoid the differential settlements. 
This unique project is now almost completed and very few small small things are remaining. See It has an elegant look at night for lights. Thanks to the experienced contractor who didn't ruin the design and gave the nice finish and same sight as in the 3d modal. 

House of an Electrical Engineer in Hokandara

This two story housing unit was proposed to build in Hokandara area near Colombo. The Architectural Design was done by Mr:Chathura Perera. The total land area is 9.8 Perches and the total floor area of the house is 3060 square feet. The ground floor is consisted with a single car parking slot and the side road with the dead end could be used for additional ceremonial parking. 
In the ground floor 1 bed room with attached bathroom, living room,  kitchen, servant's room and toilet are placed. The Architect has taken successful effort to have a more spacious look inside the house. So in the first floor he has designed like two reinforced concrete slab parts connected to each other by a small narrow timber deck which is supported on two Steel "I" beams. In the either sides of that small bridge type arrangement double height spaces were placed. In the first floor master bed room is placed with the nice look of the paddy fields through the side road. another two bed rooms are placed in the rear side of the house with a common bathroom.
    the top slab of the parking area has used as the first floor open terrace to the sky with a flower trough. The second floor terrace is used as the larger ceremonial open terrace area. Another third slab is placed to cover the stairs and it is proposed to utilize as the water tank slab.
        
    The structural design is done by Chartered Structural Engineer, Isuru S. Amarasena. He has visited the site initially and looked at the side conditions and the soil conditions. As a hard type kabok soil strata was identified through out the land under 2 feet from the existing soil 3x3, 3.5x3.5  sized pad footings could be used for the substructure. In order to compliance with the Robustness Criteria, 9x9 tie beams were prosed with T12 Diameter reinforcement bars with R6 stirrups at 125mm interval spacing. Rubble foundation with different sizes were proposed for different areas of the house according to the considerable level differences. One blind wall (Blind end) is faced to a existing boundary wall with a longer height of the neighboring land and special attention was given for that side. Separation of two structures and water tightness were taken in to account when designing them. In order to avoid the strap footings which needed a high attention and a high cost, the columns at the blind end are shifted towards the house inside the walls. So no, eccentric footings were used for the constructions. Below are few images taken during the foundation construction stage. 

Here you can see the pad foundation base pits with their reinforcement nets. The soil excavation is done in an effective way considering the required depths for the rubble wall foundation depths and tie beams. 

This image is taken after placing the rubble foundations. The column reinforcement has come out of the pad bases. 

2 Story House at Bataduwa, Galle

After the construction works done, the house's front view image is attached below. 
During the constructions very few slight modifications has been done. This photo was taken before the landscaping work.

 
The site was situated in the down south of Sri Lanka, very close to the Galle town area. The place had an old single floor housing unit and the same area was utilized for the new house, after demolishing the old one.

A different type of weak soil layer was found near to the rear end of the building and as well as near an old toilet pit. The base pits were excavated to a certain depth by looking for a stable soil and as an additional safety precaution concrete rings (Cylinders) were used and inside the ring a compacted quarry dust layer was used. With this process it is believed that the differential settlements were tolerated if any. 

Around 20  umbers of columns and column bases were used for the housing project and three floating columns were used for maintaining the architectural requirements as it is. 

These images show some steps during the structural modal analysis. 
The first one shows the axial forces acted on columns. But it is not the only governing factor of reinforcement for columns. The bending moment also should be considered.

Below two images denote the slab stresses.

Below image shows the deflected shape of the building due to the loadings. You can clearly see the deformed beams and columns here. In order to withstand straight in the application of loads we have to provide the steel requirements in those places. But providing the same reinforcement area for the entire element doesn't give an economical design. So design optimization should be taken in to account in house designing. 

After the construction Stage, The final outcome can be Seen here below.