Katendiarvutuse analüüs

Käesoleva lõputöö eesmärk oli analüüsida teekonsruktsioonide projekteerimise käigus tehtavate rattatüübi valikute mõju lõpptulemusele, konstruktsiooni maksumusele ning võrrelda tulemusi Soome metoodikaga. Töös kasutatud algandmed pärinevad Transpordiameti tellitud ning T-Konsulti koostatud tööst (Raskemate ja pikemate veoste mõju arvutamine riigideete taristule). [9] Töös kirjeldatakse Katendiarvutuse metoodikale omaseid uuringuid ning võtmetähtsusega valemeid, mille alusel programmid arvutusi sooritavad. Lõputöös uuriti paaris- ja üksikratta mõju erinevate liiklus- ja koormussageduste puhul katekndikonstuktsioonile ning maksumusele. Võrreldi KAP paaris- ja üksikratta arvutuste tulemusi KRP-ga. Viidi läbi uuringuid riigiteedel ning võrreldi varasemalt projekteeritud teekonstruktsioone KAP-is arvutusega, kus eeldati üksikratta kasutust. Lisaks uuriti kuidas on arvutatud hetkel kasutuses olevad siirdetegurid. Võrreldi liikluse struktuuri erinevates riigiteede kategooriates ja ka üksikrataste osakaalu Eesti liikluses. Arvutused paaris- ja üksikratta konstruktsioonidele viidi läbi teeklassides 1-4. Tulemusena selgus, et üksikratta kasutusest tulenev kallinemine tekkis ainult 1. ja 2. teeklassides. Sellest saab järeldada, et väiksematel teeklassidel on topeltratta arvutuses piisav varu, et tagada ka kindlus üksikratastele, kuna autorongide osakaal madalamaliigilistel ja väiksema koormusega teedel on väiksem. Lisaks selgus, et KAP-i tulemused ei sõltu ainult teeklassist, vaid ka koormussagedusest. Mida kõrgem on teeklass, seda väiksemad on lubatud tõmbepinged ning seda suurem on ka rattateguri mõju. Lõputööle seatud hüpotees pidas paika ainult osaliselt. Töö käigus selgus, et kogu Eesti teedevõrgu korraga üles ehitamise puhul on üksikrattale projekteerides tulemus tõesti kallim, kui paarisrattale, kuid seda ainult 1%. Kahe rattatüübi hinna erinevus tulenes AC base kihi paksusest. AC base kihi eesmärk on tagada eelkõige kandevõimet ning üksikrattast tuleneva suurema koormuse tõttu tõusis ka selle asfaldikihi paksus. Teekonstruktsiooni kallinemine üksikratta arvestamisest on marginaalne, võrreldes arvestuslike kuludega üleminekust teisele programmile, sest Soome metoodikat KAP-i üksikratta arvutusega võrreldes on hinnavahe 11,8%. Siiski ei saa KAP kasutuse jätkamist pidada perspektiivseks tuginedes 2016 ja 2022 uuringute järeldustele nii otseste kui kaudsete vigade tõttu KAP algoritmides ja loogikas. 41 Uurimise käigus viidi läbi ka katendi eluea analüüs mille tulemusel selgus, et paarisratta arvutuse tulemusena säästetakse 1% rahas, kuid kaotatakse tõenäoliselt 20-30% konstruktsiooni elueas – seda siiski vaid väga väikesel osal riigiteedest (3,5%). Praegune katendiarvutuse metoodika on välja töötatud ajal, kui teedel liikuvad sõidukid ning nende rehvid olid tänapäeval kasutatavast paljuski erinevad. Selleks, et saada teada, kas KAP-i üksikrattale projekteeritud teed oleks ka praktikas piisavalt tugevad, et tagada teede pikem eluiga, tuleks teha veel põhjalikumaid uuringuid ja analüüsida tegelike tuvastatud defektide põhjuseid.

The aim of this thesis “Analysis of Pavement Design” was to analyze the impact of the wheel type choices made during the design of road structures on the final result, the cost of the construction, and to compare the results with the Finnish methodology. The original data used in the work comes from the work commissioned by the Estonian Transport Administration (Transpordiamet) and prepared by T-Konsult (Calculation of the impact of heavier and longer loads on the infrastructure of state roads). [9] The thesis describes the studies specific to the pavement calculation methodology KAP and the key formulas on the basis of which the programs perform calculations. In the thesis, the effect of a twin and a single wheel on the pavement structure and cost in different traffic and load frequencies was studied. The results of the calculation of twin and single wheels in the pavement calculation program KAP based on Estonian guideline were compared with the calculations made with the pavement calculation program KRP that is based on Finnish guideline. Studies were carried out on state roads and previously designed road structures were compared in KAP program with a calculation assuming the use of a single wheel. In addition, the author studied how the transition factors currently in use have been calculated. The structure of traffic in different categories of state roads, as well as the share of single wheels in Estonian traffic were compared. Calculations for twin and single wheel structures were carried out in road classes 1-4. As a result, it turned out that the increase in cost due to the use of a single wheel occurred only in the 1st and 2nd road classes. It can be concluded from this that smaller road classes have sufficient margin in the calculation of the twin wheel to ensure also the safety of single wheels, as the share of trailer trucks on lower-type and less-loaded roads is smaller. In addition, it turned out that the results of KAP calculations depend not only on the road class, but also on the load frequency. The higher the road class, the lower the permissible tensile stresses and the greater the effect of the wheel factor. The hypothesis set for the thesis was only partially correct. In the course of the work, it turned out that in the case of building the entire Estonian road network at once, when designing a single wheel, the result is really more expensive than for a twin wheel, but only 1%. The difference in price between the two wheel types was due to the thickness of the AC base layer. The purpose of the AC base layer is first and foremost to ensure load-bearing capacity, and due to the increased load from a single wheel, the thickness of its asphalt layer also increased. 43 The increase in the cost of road construction compared to the calculation of a single wheel is marginal compared to the estimated costs of switching to another program, because the price difference when comparing the Finnish methods to KAP for a single wheel is 11.8%. However, the continued use of KAP cannot be considered prospective based on the findings of the 2016 and 2022 studies due to both direct and indirect errors in KAP algorithms and logic. In the course of the research, an analysis of the lifespan of the pavement was also carried out, as a result of which it turned out that as a result of the calculation of the twin wheel, 1% of money is saved, but 20-30% is likely to be lost in the lifetime of the structure – however, this is only in a very small part of the state roads (3.5%). The current pavement calculation methodology was developed at a time when vehicles on the road and their tires were very different from those used today. In order to find out whether the roads designed by KAP for the single wheel would also be strong enough in practice to ensure a longer life of the roads, even more in-depth studies should be carried out and the causes of the actual defects detected should be analysed.