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How to estimate construction time? How to coordinate all tasks, taking into account weather conditions, the availability of subcontractors or the need to work under ‘live traffic’? We cover this on our latest story on time management at the construction site.

Recently, we wrote about how an investment implementation schedule is developed. One of its elements is the performance of construction works themselves, which also requires proper planning. It is extremely important that during their performance the general contractor does not skip any task and performs each at the right moment. This is why a separate construction site schedule is established.

A planning specialist asked about where it all starts, will surely answer: ‘from the assumptions’. The most important assumptions for any construction site are the so-called milestones: key dates in the life of a project, e.g. the date of launching and completing works. Once these are defined, you can start the four-stage process of developing a construction schedule.

Stage I – introducing tasks

The construction of a tram route is not limited to laying tracks and building an overhead power supply. A series of tasks is involved some of which – at first glance – may seem unrelated to the main purpose of the construction, like removing the old asphalt or laying a new gas pipe. The schedule must cover everything that is necessary to deliver the infrastructure in accordance with the assumptions and the order on time.

The same tasks at different stages of construction may appear in the schedule as general entries or items described in detail. – While on a very fresh construction site we break down tasks such as methods of ground strengthening, and we only mention finishing works, on a mature construction site we focus on painting walls at underground stops or driving in road barriers next to freshly laid asphalt – says Wiktor Walicki, a planning specialist with Gülermak, the company building the Tramway to Mistrzejowice.

Determining the sequence and degree of detail at the individual stages of construction is not enough to complete the works within the deadlines. It is still necessary to determine their duration, link them together and optimize them.

Stage II – Specifying the duration of individual tasks

How long will specific works take? This can be estimated using one of three methods. If the general contractor has completed works in similar conditions, it can rely on performance data from other construction sites. A good example would be the construction of diaphragm walls: knowing the surface of these walls to be dug per day, it can estimate the number of days required to complete a certain range on a construction site. However, this method can only be used for large jobs; it is not suitable for small ones.

A manager of works in a given discipline (e.g. grid) can also be helpful in estimating the duration of less repetitive tasks. Having information about the parameters of a task, he/she uses his/her own experience and calculates the projected period to complete the task. Laying a new gas pipe would be a good example. The duration here would depend on its depth, diameter, length of the section and obstacles to be dealt with.

Finally, if the general contractor hires a subcontractor for some tasks, the latter may provide estimates made on the basis of its practices. An example here would be the sowing of lawns or the installation of catenary poles for the trams.

Stage III – linking the tasks set

Although the order in which individual works are performed is important, it does not mean that they are always made one after the other on a construction site. Sometimes they can be handled simultaneously, other times coordinated so that they end at the same time. Other times, you can foresee an appropriate timing between the end of one task and the start of another.

– Imagine you have to excavate and make a fill next to each other. In this case, it seems logical to do both at the same time – you simply transfer the earth. On the other hand, if you pour a concrete slab, once it is completed you have to wait a few weeks for the concrete to dry in order to be able to put waterproofing on it – says Wiktor Walicki.

The planning specialist must therefore link the tasks in the so-called bundle. Often times, this is done taking into account various external factors, e.g. the need to keep roads passable, the supplies of construction materials, availability of subcontractors or the season (you wouldn’t plant trees in winter, would you?).

Stage IV – optimization

Even after all these efforts, it may turn out that you are still unable to reach the milestones in the intended time. You then take another look at the schedule. There must be some opportunities left to optimize it – e.g. by increasing staffing and thus efficiency, launching certain tasks earlier or performing them simultaneously with others.

The beginning of next year will see the launch of the construction of another tram route in the north of Krakow – however, this is not an investment you’ve seen before. Not only is it implemented in the PPP formula, but it is also precisely adapted to the needs of a modern city.

An investment unlike any other! Although the idea of building a tram route to Mistrzejowice dates back to the times when the main city arteries were designed in a completely different way, the latest design reveals a space that the residents were striving for – friendly to all traffic users, sustainable, green. Created with future generations in mind.

– In recent months, work has been continued on the design of the tram route to Mistrzejowice. The aim was to adapt the solutions to the requirements of a modern city where every user feels comfortable. This investment is far more than just a fast tram to the city center. We’re talking residents-friendly, green area, safe routes for pedestrians and cyclists, infrastructure adapted to the changing climate – says Marcin Hanczakowski, Director of Kraków Municipal Road Authority (ZDMK).

Green tramway to Mistrzejowice

As a reminder: the KST IV route is to connect the area of Jancarza Street with the intersection of Meissnera and Mogilska Streets – from there passengers will quickly get to the Mogilskie Roundabout and further to the city center. Cars will be running along Bohomolca, Dobrego Pasterza, Lublańska and Młyńska Streets – partly as a grade-separated solution because from the Barei Roundabout to the Młyńskie roundabout at level -1.

There are actually quite a lot of changes introduced which were recently requested by residents (mainly those in the area of Meissnera and Młyńska Streets). You will definitely notice a significant reduction in the number of noise barriers, commonly considered to be eyesores in urban areas, and an increase in the amount of greenery designed along the route. – After receiving the contracting authority’s consent to narrow the cross-section of Meissnera Street, we reviewed the forecast traffic volume on this thoroughfare and repeated the acoustic analyzes. Their results supported abandoning most of the designed noise barriers. In turn, local changes in the geometric layout of sidewalks and underground routes of systems allowed to additionally keep approximately 200 trees and find room for new plantings – says Paweł Motyka, Deputy Project Manager for Gülermak, the company making the investment.

In total, over a thousand trees will be planted along the entire tram route and the Mistrzejowice terminus will be transformed into a new park. Decorative grasses and shrubs, a rain garden, vines will be introduced in representative areas. Roofs of tram stops will feature stonecrops, i.e. dry-loving plants that are increasingly popular in public space. Along the entire route – apart from the tunnel, ramps and intersections – a green trackbed will be introduced. Trees will be planted even on bus stop platforms where Kraków residents look for shade so often.

The contractor convinces that traffic noise will also be minimized thanks to the use of the BBTM silent surface, which has not been used so far in Kraków, track lubricators and the state-of-the-art trams and buses.

Modern city requires modern solutions

The implementation of the new route in the public-private partnership (PPP) formula actually forces the use of environmentally friendly and technologically advanced solutions. The entity building the new route will also maintain it for 20 years, which obliges it to ensure relative reliability. This is to be ensured by advanced supervision systems over the operation of the tunnel under the Polsadu roundabout, traffic control and two innovative catenary substations (supporting central – remote control and supervision) securing the power supply on the new section. State-of-the-art passenger information system that allows precisely estimating the time remaining until the arrival of the tram and planning transfers. Two multi-level communication hubs (at the Młyńskie and Polsadu roundabouts) will ensure convenient transfers between the ground level and underground parts (also for people with limited mobility). Already at this stage, the designer took into account possible future expansion of the facilities to support a pre-metro route, including a section shared with KST IV, and the architect made sure that the underground stations draw on Kraków’s traditions and modern trends alike. The designs are indeed impressive!

Strolling like never before

Back to the surface. Not only trams and cars will be moving here, but also pedestrians and cyclists so often disregarded in large infrastructure projects. A coherent network of sidewalks and bicycle paths along the entire route will definitely improve their situation. Bicycle and pedestrian traffic are separated from each other and from car traffic for the most part of the route, which reduces the risk of collision – and thus – increases safety. The routes are to be lightened up. The prospect of a walk or a bike ride seems all the more attractive once you have something to sit on and something to attach your bike to. In this respect, the Mistrzejowice terminus with benches among the trees and a bicycle parking lot stands out in the design. It will be an investment unlike any other before and the kick-off is in a few months!

The process of re-arrangements regarding limited traffic in Meissnera Street has started. As a result, the number of noise walls along the project will be lower and the space created can be designated for greenery.

– The current street will be narrowed. Thanks to it, there will be less asphalt, more greenery and fewer noise walls – explains the designer, Krzysztof Markowicz from Arcadis, the company responsible for the design of the tram route to Mistrzejowice. More information about the changes to the immediate vicinity of the tram route to Mistrzejowice can be read here.

Tramway to Mistrzejowice meets the expectations of the residents

Implementation of the initiated changes requires not only additional design works but also arrangements with a number of institutions, among others owners of buried services (e.g. water lines, fiber-optical cables) or the City of Kraków’s Municipal Traffic Engineer. The process of arrangements is already underway. Soon, we will know how they will affect the project schedule.

– The designing stage will last a little bit longer but thanks to it, the new tram route will even better meet the expectations of the residents – says Michał Pyclik, spokesman for the Kraków Municipal Road Authority.

Over 18 thousand m² of bike paths will be constructed as part of the construction of the Kraków Fast Tram route (KST), stage 4.  Cyclists will safely and comfortably cover the entire route between the intersection of Meissnera/Mogilska Streets and Mistrzejowice.

Two-way cycle tracks are being designed along Meissnera, Młyńska, Lublańska and Dobrego Pasterza Streets on both sides of the route to the level of Krzesławicka Street. Cycling continuity between Dobrego Pasterza and Bohomolca Streets will be provided along Krzesławicka Street where cyclists will participate in general traffic. Along Bohomolca and Jancarza Streets, a cycle track has been designed on one side of the road to the Mistrzejowice terminus. They will be integrated with the existing network of cycle routes.

Safety and comfort on the cycle track

According to the design, car traffic, cyclists and foot traffic will be separated.  – Sidewalks and cycle track will be separated from each other by means of different pavement texture – says Magdalena Cyran, road design coordinator in Gülermak, the company implementing the KST IV project.

The cycle track pavement will be made of asphalt concrete in order to ensure comfort and safety for cyclists. The applied solutions will guarantee good adhesion on curves and during wet braking. They will minimize the risk of cracks, chips and deflections caused by various factors, e.g. impact of vegetation or low temperatures. Thanks to the red color of the wearing course on cycle crossings, the zone for cyclists will be visible and aesthetic.

The required visibility has been verified and ensured at all spots where the cycle route crosses other travelways. The designer has verified visibility splays and obstacle-free-zones have been introduced where necessary. They will ensure greater visibility both for the vulnerable road users and drivers thanks to which quick reaction will be possible.