Background
According to the article “Climate of Singapore,” Singapore is situated near the equator and has a typically tropical climate, with abundant rainfall, high and uniform temperatures, and high humidity all year round. Through the recent years, Singapore has been facing flooding issues occasionally due to the increase in the average temperature of the Earth’s atmosphere and the outdated stormwater management system. As a result, Singapore Institute of Technology (SIT) faces similar flooding issues whenever there are heavy recurring rains. Currently, there is a lack of implementation of anti-slip pathways to facilitate SIT’s population under these heavy downpour circumstances based on observations and personal experiences. This results in many instances whereby slip and fall are prone to happen. Also, with the pavements being impermeable, flooding and “ponding” are bound to occur when it rains and this causes inconveniences for SIT’s population as footwears and clothes get drenched.
When a Slip and fall incident occur on a property (or “premises”) owned or maintained by someone else, the property owner may be held legally responsible (“Slip and Fall Accidents Overview,” n.d.). There were actual cases whereby a slip and fall incident has resulted to the victim filing a lawsuit against the property owner. According to an article from The New Paper, a man slipped and fell at a sheltered walkway and as a result, suing the town council after he became paralyzed due to the fall. Ultimately, as a technical educational institute, a slip and fall incident is certainly an issue that SIT would want to prevent.
Being the fifth autonomous university in Singapore, there are numerous reputable stakeholders that visit SIT for seminars/talks. When these stakeholders visit the school, they will walk along the aforementioned sheltered walkway and when it rains and starts “ponding”, it will leave a negative first impression about the school. This is mainly because the walkway is outdated as these “ponding” occurs due to the usage of impermeable concrete, and the poor drainage system. As a result, SIT’s reputation may be affected as these types of safety precautions should never be overlooked.
Problem statement
In order to prevent slip and fall incident from happening in SIT@Dover, installing anti-slip pathways will mitigate ‘ponding’ or flooding whenever it rains. However, there is a lack of implementation of anti-slip pathways to facilitate SIT’s population under heavy downpour circumstances. This results in various instances where slip and fall are prone to happen. Implementing the use of pervious and anti-slip pathways will, therefore, reduce inconvenience to users as it mitigates ponding when it rains heavily in SIT.
Purpose statement
The aim of this report is to propose to SIT’s division of estates the implementation of pervious pathways along 3 flood-prone areas around the campus in order to create a safer environment for the community. The 3 areas that will be focused on are front and back gate sheltered walkway, and the walkway that leads towards the University Services Centre from the back-gate entrance.
Proposed Solution
The team has proposed a solution whereby pervious anti-slip pathways are to be implemented along the previously mentioned areas. These areas were chosen as they are prone to “ponding” especially during heavy recurring rains which happens frequently these days.
Pervious concrete pavement is a unique and effective means to address important environmental issues and support green, sustainable growth. By capturing stormwater and allowing it to seep into the ground, pervious concrete is instrumental in recharging groundwater. Pervious or permeable pathways differs from traditional pathway as it allows water to infiltrate through the surface, thus preventing “ponding.” How this is achieved is by using pervious concrete instead of ordinary concrete. A pervious concrete mixture contains little or no sand, creating a substantial void content. Using sufficient paste to coat and bind the aggregate particles together creates a system of highly permeable, interconnected voids that drains quickly. Typically, between 15% and 25% voids are achieved in the hardened concrete (Pervious Concrete Pavement, 2011). When concrete is manufactured, the amount of water used in the mix is crucial. Water to cement (w/c) ratio is used to determine the amount of water and cement accordingly. Ordinary concrete typically has a w/c of 0.6 to 0.7 whereas pervious concrete has a ratio of 0.28 to 0.4. The lower the w/c means the mix is more ‘dry’ therefore creating more voids for water to seep through.
As the current material used along the walkways are regular cement, the replacement of porous anti-slip pathway will now enable storm water to be absorbed into the collecting basins underneath. By reducing ponding on the surface and having anti-slip tiles, it creates a much safer walking area as more friction are present. This can therefore, decrease the likelihood of a slip and fall incident from occurring.
In order to ensure that this proposed solution can be implemented in an effective manner, the walkway connecting University Service Centre (USC) to the back gate will be taken as the “controlled” factor such that it will be the proposed location for this project. This is so that SIT’s division of estates are assured that the area that is first considered as a “prototype”, is fully located in SIT@Dover’s campus. Concerning the fact that this project may cause obstructions to students as it may be inconvenient to travel from one location to another, this project is to be reconstructed over the trimester break, whereby there will not be as many students and faculties around, so as to minimize the amount of inconvenience caused.
Potential Solutions
Besides incorporating pervious concrete in order to overcome the ponding issue, there are various other potential solutions that can be considered. Such examples include the gradient of the slope, whereby a pathway is generated for water to flow into the nearby drains. Alternatively, the method of stamping on existing concrete in order to create friction may also be an idea that can be studied to further improve the use of pervious concrete.
The slope of the pavement plays a major role in the current issue of flooding. Based on the article, “Flooded Basement? How to Deal with Common Causes,” it stated that one of the causes of flooding is due to pavement slope. The article also mentioned that the pavement would settle over time and that would affect the gradient and direction of the pathway. If that happens, the solution is to remove and replace the pavement so that it will slope in another direction. Creating a slope in the opposite direction helps with the flooding as a pathway has been generated for the stormwater runoff to be directed towards an area such as a patch of grass, or an open space that is not prone to flooding. By doing so, the pavement would be kept dry and people would not have a hard time trying to walk as slowly as possible to avoid splashing of muddy or dirty runoff on their shoes or pants. The cost of changing the slope of the pavement is relatively cheap as it can be hack away and then recast concrete on it. However, the process of changing the slope would affect the community as they are unable to travel along the pavement when it is being reconstructed.
Stamped concrete is another alternative that could be implemented. It is basically a patterned and/or textured concrete to look like a brick, wood or any texture desired. This method is cheap and has the least maintenance compared to the rest. Apart from that, ease of installation is also an advantage for this method. It is also longer lasting than most of the other alternatives. However, durability is an issue as it has low durability compared to other surfaces and methods. This is a good method for creating customized looks for patio, pool side tiles or even backyard as it focuses more on aesthetic rather than solving the issue at hand.
Another simple alternative would be to introduce a drainage system along the pathways mentioned.Currently, there are no visible drains along these troubled pathways which could be the main contributing factor to these ‘ponding’ issues.
Benefits
The team’s main priority for proposing this project is the safety of the SIT community. There are various advantages when it comes to using pervious concrete. Firstly, such advantages include the environmental benefits. When it comes to providing benefits to the environment, pervious concrete is able to eliminate runoff, recharge groundwater, and even eliminate the need for retention basins and water collection areas. Not only that, suspended solids and pollutants will be trapped within the pervious concrete, therefore reducing the chances of “ponding.”
Secondly, another advantage when it comes to using pervious concrete, is the financial benefits. The implementation of pervious concrete eliminates the costs for retention basins, curbs, gutters, and other water collection installations. It also provides lower installation costs as no underground piping, storm drains, or sloping/grading are needed. The low life-cycle costs of pervious concrete can be compared with regular concrete such that it has an equal life expectancy to that of regular concrete: 20 to 40 years when correctly installed.
Lastly, the anti-slip tiles would provide the necessary friction needed to prevent users from slipping especially during heavy rains and thus reducing the inconvenience experienced amongst the users now.
With all these benefits in mind, SIT’s division of estates can certainly reap the benefits. Instead of utilizing the ordinary concrete when developing a walkway, executing the use of pervious concrete in a college campus will certainly have a positive impact on the school’s image. Besides that, external stakeholders such as Land Transport Authority (LTA) may also incorporate this idea along the sheltered walkway from the back gate bus stop to the entrance of the campus. Especially, considering the fact that flooding always occurs at that area whenever there is heavy rain. By incorporating the use of pervious pathway, this recurring issue will definitely be solved.
Evaluation
Though there are various benefits to using pervious concrete, there are certain restrictions and doubts that come from this proposed idea.
A pervious pavement project should be properly designed to accommodate the amount of stormwater runoff that is expected in the area. If not adequately designed, the water table below the pavement can rise, preventing stormwater from being absorbed into the ground. Certain types of pervious pavements require frequent maintenance due to the possibility that solids and particles may get trapped and clog pavement pores. If the proper “vacuuming” or flushing is not carried out, pervious concrete will assume the traits of impervious concrete. While it is estimated that porous concrete can be two to three times more expensive than regular asphalt or concrete, cost savings are simultaneously achieved as stormwater installations are not necessary.
Besides that, the team also went ahead to interview a fellow lecturer atSIT@Dover, Dr Feijin, who specializes in concrete materials and design. He mentioned that because pervious concrete has such a high void content and its overall strength is generally lower than that of regular concrete, it is not recommended on heavy loading areas. In view that this project is to be implemented along the sheltered walkway leading towards USC from the back gate, utilizing pervious concrete at this area seems to be the best choice as this part of the school is not a place where heavy loadings are applied.
Apart from interviewing Dr Feijin, the team has also gathered relevant facts regarding the use of pervious concrete from a professional engineer over at an engineering company called SamWoh Corporation Pte Ltd which is one of the leading companies that specializes in ready-mix concrete. They explained that although pervious concrete has its advantages, one of the main drawback of using it widely is the maintenance. As mentioned in the article “Permeable Pavement: The Pros and Cons You Need to Know,” The concrete is prone to clogging if the water in the reservoir is not drained out properly. As a result, an industrial vacuum would be needed to unclog the sand and fine particles that clog the voids. If this was not done properly, water would start to ‘pond’ on the surface, defeating the whole idea of reducing ‘ponding’ occurrence.
Replacing the current concrete to the pervious ones would definitely not be a simple process. It would require the pathway to be blocked off for construction works to be done. A temporary pathway wont then need to be constructed to allow the pedestrian to move along the back gate and USC while construction is done along the pathway.
Methods/Procedure
In order to ensure sufficient knowledge is gained before implementing the use of pervious concrete, various research was done initially to ensure the team has an in-depth understanding when it comes to the laws here in Singapore. To narrow down the research, the team decided to search on the guidelines provided by Building Construction Authority (BCA) regarding floor surfaces, standard measurements in Singapore when it comes to how smooth or rough the floor can be, and statistics on the number of people that experienced a “slip and fall” incident.
According to the guidelines provided by (BCA), it is stated on the code of accessibility, “In The Built Environment 2007,” floor surfaces shall –
(a) be stable, firm, level and slip-resistant;
(b) not have any projection, drop or unexpected variation in level;
(c) have colour and tone that are contrasting with the walls, otherwise, the skirting must provide a clear distinction between the floor and wall; and
(d) Where there is a change in level, contrasting colour bands are to be provided to alert the users of the change in level.
The guideline also provided grading of the slip resistance of some of the typical materials used for floor finishes. Attached as Appendix B.
According to the quality standard of floors provided by BCA (BCA: Quality standards, 2009), the standard measurements in Singapore when it comes to how smooth or rough the floor can be, are as follows:
- No stain marks
- Consistent colour tone
- Evenness of surface (not more than 3mm per 1.2m)
- No ponding in falls for wet area
- Falls in wet areas should be in right direction
- No hollow sound when tapped with hard object (for Ceramic, Marble & Granite only)
- No sign of delamination
- Consistent skirting thickness and no visible gap between wall and skirting
According to the website from WSH Council, it is stated that slips, trips and falls (STF) are the most common causes of injuries in workplaces. STF injuries contributed to more than 20% of all workplace injuries and hurt more than 1,000 employees every year. Besides sprains and strains, STF can also cause more serious injuries like fractures and head injuries.
Slip, Trip and Fall Hazards
Examples of factors that may increase STF risks include:
- Insufficient lighting;
- Poor housekeeping;
- Wet and slippery floor and surfaces;
- Lack of handrails on platforms or staircases;
- Unsafe use of ladders;
- Uneven walking surfaces
Apart from conducting research on the guidelines from BCA, a survey was conducted around SIT@Dover campus to find out what the students and faculties experience when they walk along the mentioned sheltered walkways whenever it rains. Each of the project members was given a task to survey 3 people each so as to get sufficient data to prove that this is an ongoing problem in SIT@Dover. In order to ensure that the survey is not biased, members of the community were also considered as part of the subject of the survey besides students. The questions asked and the results collected are as follows:
Question 1: Have you ever slipped/fell along the pathway connecting USC and the back gate?
Results: Out of 12 people we surveyed in total, 9 of them said yes.
Question 2: On a scale of one to ten, how safe do you feel walking along that pathway when it rains heavily? (1 = Safe, 10 = Unsafe)
Results: The average number we gathered from the same 12 people is about 7.
Question 3: On a scale 1 to 10, How convenient is it to walk along that pathway when it rains heavily? Etc getting drenched, slipping. (1 = Very convenient, 10 = Inconvenient)
Results: The average number gathered is about 8.
Based on the results gathered, it can be concluded that most of the SIT@Dover population agrees with this hypothesis. Given that, reputable sources were interviewed to ensure the proposed solution is doable and feasible.
As such, the team interviewed a fellow lecturer, Dr Feijin, who has a Ph.D. on concrete materials to provide insights of pervious concrete. The main question directed to him was regarding the fact that if pervious concrete costs cheaper than regular concrete. He responded by stating that pervious concrete has been in place in many parts of the world now. It is a tested method to reduce “ponding” issues. However, it has lower strength compared to regular concrete due to its increase in void spaces that allow water to seep through it. Nonetheless, it has more than enough strength to withstand the load.
Apart from that, we also manage to interview the manager of SamWoh while on our learning journey. He gave similar insights about pervious concrete as Dr Feijin did with an additional comment stating that the maintenance is the main drawback for pervious pathways to be used regularly.
Concluding Statement
In conclusion, the main takeaway from this proposal is the safety of the SIT@Dover population. Replacing the current traditional concrete with pervious concrete should be implemented in order to achieve the safety desired. Every method and/or solution has its disadvantages and that goes the same for pervious concrete as maintenance is the main drawback for pervious concrete to not be implemented widely. Apart from that, compared to regular concrete, pervious concrete cost higher due to its specific w/c ratio to achieve the porosity. However, change has always been expensive but change has to be looked at as a long-term investment as evident from changing normal lights to light emitting diodes (LED). According to the article “Out with fluorescent garage lights, in with LEDs,” A “normal” 48″ fluorescent tube light is around $6 or $7 per light. While the LED bulbs are more expensive by a mere $3 difference, it isn’t much at all given the lower energy usage and long life. Change does not happen overnight and most people resist to change due to contemplation. The constant denying of the problem at hand is the main reason change has been neglected for the most part.
On the other hand, some of the benefits porous concrete brings includes environmental benefits. It mimics the drainage and filtration of natural soils hence the storm water collected at its basins are cleaner than those usually collected by using rains. Another important factor it brings is financial benefits for developers. It eliminates the need for the costly stormwater detention vaults and piping systems as the pathway itself is a detention area and also the cost of curb and gutter installation. In summary, using pervious concrete would definitely have more benefits in the future economically and environmentally.
Just to add on, when the trial of this pervious anti-slip concrete is successful, other campuses in Singapore could also adopt these similar changes to further improve the safety of its campus population. Not only that, the future SIT campus at Punggol could also use this pervious anti-slip concrete as not only it improves safety, it also allows the developers of that campus to have more space for construction as pervious pathways will remove the need for drains, piping and collection basin needed for traditional pathways.
