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Categories and types of flood adaptation measures applicable in the design of public spaces
Published in Maria Matos Silva, Public Spaces for Water, 2019
Indeed, a permeable pavement can become impermeable if the aforementioned factors are not taken into consideration. In other situations, a paved surface may reach its maximum load capacity as a consequence of being frequently used and/or by sustaining heavy weights, compressing the pavement’s structuring layers to a point where no water infiltrates. This phenomenon is frequently observed in densely populated and compact urban areas where the typical Portuguese pavement Calçada Lisboeta is applied. Despite it being a pavement that is generally characterized by being semi-permeable, in most situations, namely in Lisbon’s center, this pavement is entirely impermeable.
Improving design of bituminous mixture through service-oriented specifications
Published in Maurizio Crispino, Pavement and Asset Management, 2019
D. Gardete, L. Picado-Santos, S. Capitão
The following factors were typified: Traffic – Traffic classes were defined based on the Portuguese design guidelines (JAE, 1995) using the accumulated number of 80 KN Equivalent Single Axle Load (ESAL). However, to simplify the proposed procedures, the number of classes was reduced from 8 to 5 (Table 2).Temperature – Aiming to better represent the Portuguese climatic conditions, the summer temperature was selected as the relevant factor. The summer temperature is already included in the Portuguese pavement design specifications, with the definition of 3 zones according to the average summer temperatures: mild, medium and high (JAE, 1995). For structural pavement design, mild zones have weighted summer temperatures in general bellow 24°C and hot zones above 28°C (Baptista and Picado, 1999). Since, pluviometric and summer temperature zones have similar geographic limits the inclusion of rainfall was considered redundant.Layer – At surface it was considered more significant the moisture resistance and permanent deformation resistance and in bottom layers the fatigue resistance.Type of mixture – Due to different properties of the mixtures it is not possible to have similar design parameters for all types of mixtures. For different types of mixtures design parameters are expected to vary (e.g. target air voids content and compaction levels).Performance tests – The inclusion of performance tests can bring some laboratorial validation of the mixtures. Although a large number of performance tests can be included in the design process this can make it more expensive and the design optimization more complex.
Stone pavement materials and construction methods in Europe and North America between the 19th and 20th century
Published in International Journal of Architectural Heritage, 2019
Erika Garilli, Felice Giuliani
A truncated pyramid was the ideal shape of the elements, and its use remains popular. The large base, which may be square (as for most Italian stone pavements) or rectangular, was turned upward, and the lateral sides were roughly carved to create greater adhesion to the bedding layer. In the United States, streets with an exceptionally large longitudinal slope presented elements set with their broadest edge down (Gillmore 1876). In other locations, especially in Central Europe, cubic elements were widespread (Baker 1906; Castells 1934; Gautier 1721). The size of the elements had a key role in the stability and functionality of stone pavements. When determining the depths of elements, their stability and the amount of wear to which they were subjected were considered, and a depth of approximately 20 cm was generally recommended. The upper surface of the elements, which is also referred to as the “head”, had to be small to provide a suitable foothold for draught animals; moreover, if the elements were too big, they may tip under traffic loads. The elements did not have to be very small to avoid having too many joints and low vertical strength. In specifications adopted for paving the city of Havana, Tillson (1900) indicated that the maximum width of elements was approximately 7.5 cm because a mule instead of a horse was principally used as a draught animal. Some examples of the stone elements used in Italy, Europe, and North America for the construction of road pavements are listed in Tables 1, 2, and Tables 3. A particular type of stone pavement is the “Calçada Portuguesa” (Portuguese pavement), which was introduced in 1848 and consisted of small stone elements of different colors, generally black and white, and various surface shapes, such as square, hexagonal, and irregular, which were arranged to form different patterns or pictures like a mosaic (Bairrada 1985; Henriques et al. 2009).