[Construction & Technology] Assignment 2b: Site study

On this assignment, we were required to pick a location/site and to study structural elements that could be found on that site. We've picked a residential place in Denai Alam.

We've decided to choose a few structural elements to be studied. Firstly, from the extension porch at the side of the house, the columns, slab, and sliding door can be found. Secondly, the wall located at the living room area of the house, which consists of walls, columns and openings (door and windows.). And third, the staircase as the final structural element.

While two of the group members have picked the first 2 area, I've chosen the staircase as my subject.

The staircase is a Double L-shaped stairs, which is also known as quarter landing stairs, where there's 2 landings, and each landing changes the direction of the stairs by 90 degrees. This stair has a total of  19 risers and 17 treads. 

Installation/construction:

Since this is a concrete staircase, it is made by first laying out the reinforcement steel bars, and then the wooden formwork where the risers are placed adjacent to it (supported by the stringer)

http://debug.pi.gr/Default.aspx?ch=70

http://www.pfsolutions.ie/images/sce/stairs.jpg

Then, concrete is poured into the formwork. The concrete is left to be cured, and after it does, the wooden formwork is then removed. 

http://howtospecialist.com/structure/how-to-build-concrete-stairs/

http://howtospecialist.com/structure/how-to-build-concrete-stairs/

Then finishes (paint, laminated flooring etc) are added to the stairs.

Reinforcement steel bars are inserted during the making of formwork to allow the staircase to bear the tension applied.

Quarter landing stairs are generally more safer than straight stairs as the falling distance is shorter compared to straight stairs, but it takes up more area. Landings in the staircase also provide a resting place for occupants to take a break (especially elderly) while climbing up or down the stairs. 

[Activity] Skeletal Construction

To understand more on Reinforced Concrete's skeletal construction, in this lesson, we were required to make a simple one-storey building that consists of a footing, beams, columns, slab and also reinforcement. using plasticine. We were asked to replicate the procedures of the RC skeletal construction. 

RC skeletal construction procedures: 

1. Formwork and Falsework were built

2. Placing of steel bars (reinforcement) in the formwork.

3. Concrete were then mixed and cast into the formwork. As the concrete cures, the formwork and falsework is then removed.

Since we were using plasticine, the steps 1 and 3 are simplified

Our procedures (working with plasticine):

1. The "steel bars (rolled- up paper)" were placed and tied to each other. We chose to use a mat slab as the footing,

 

(We made a mistake as the entire structure's steel bars were supposed to be tied together, from the footing, to the column, then the beams. Instead, we did it one part at a time, which resulted in an unstable structure.) 

2. After the footing, the columns were built on the steel bars. 

 

3. Next, the steel bars for the beams, and then the beams were built around it. 

4. Finally, the slab is placed on another final 2 steel bars which were placed across the beams.

      

The overall structure wasn't stable due to some mistakes in the procedure, but after this activity, I've learned the correct steps of RC Skeletal Construction. 

Arch Building Activity

On the 20th of April, we were split into groups of 4-5, and assigned to build an arch out of plasticine. Our group had chosen the "Tudor Arch" to be built.

We started off by building the columns, then beams as falsework for the voussoirs to be built on.

After the voussoirs had been properly placed, the keystone was inserted to complete the arch. We've decided to add side walls so that it can help stabilise the arch. 

             

the final product looked like a vege-themed arch. 

The building progress went smoothly as we've planned the structure of the arch carefully before building it. 

After building the arch, we were assigned to test its strength and stability. Two tests were given to all arches: Load test and Seismic test. 

Load test

All arches are to be given a certain amount of load, and to withstand it for a certain amount of time. 

Our arch had successfully passed the test as it managed to withstand all loads without collapsing at all. The force from the load had been successfully channelled down from the tip of the arch. 

Seismic test: 

The base where the arches were situated are to be shaken (to imitate an earthquake), and our arches were to withstand that force. 

After some time of shaking (very, very roughly), our arch broke into two pieces, separated at the keystone area. 

After discussing and investigating a little, we realised that our arch isn't balance, as one of its side was slanted instead of being upright and straight. Since the force was acting horizontally to the arch, an imbalance build would cause it to easily detach from within. 

This activity was a fun and enjoyable experience, we've learned about formwork and falsework of an arch, and also how to create an arch using the real world methods. It was also interesting to see how other group's arch survived and failed the given tests, and some arches even had really interesting designs.