V. Negro, M. Martín-Antón, J. M. del Campo, J. S. López-Gutiérrez, M. D. Esteban Paper 12:1 Crown Walls in Mass and Reinforced Concrete: The Way to Aesthetics in Maritime Works Vicente Negro, Associate Professor, Universidad Politécnica de Madrid, UPM (Spain) Mario Martín-Antón, PhD Student, UPM José María del Campo, Assistant Professor, UPM José Santos López-Gutiérrez, Assistant Professor, UPM M. Dolores Esteban, Assistant Professor, UPM Abstract Maritime works are characterized by their remarkable size, length, depth and extraordinarily great demand for natural or artificial materials. To this effect, despite functional designs or the ultimate limit state, a breakwater crown wall can increase the overall effectiveness of the structure in limiting wave overtopping. It will contribute to a reduction of volume of material required and hence the cost to achieve a given level of performance depending on the precautions to be taken on the basis of the critical discharges for functional safety (vehicles, pedestrian and buildings) and structural safety (embankment and revetment seawalls), amongst others. In many cases, bulky mass-concrete elements are designed without any steel reinforcement. Sometimes this effect causes cracking problems in large volumes. The step to slender reinforced concrete elements may take a leap to the aesthetic factor and visual landscape integration in maritime works. In addition, the use of other materials, shapes and colours can bring breakwaters and crown walls to life by creating new functions for maritime works such as a promenade, relaxation or visual enjoyment areas. The aim of this article is to reflect on the issue of bulky mass concrete elements or rebars in slender reinforced concrete crown walls and how the use of these slender elements can bring with it excellent artistic developments as well as the use of other materials in mass concrete sloping, vertical and composite breakwaters and their crown walls. Some breakwaters are no longer just mere defence works but are becoming pieces of art. Introduction The different shapes, classes and types of breakwater display cross sections with various terminations. The economic perspective of reducing material in sloping breakwaters is one of the variables of interest. It leads to reducing the number of armour layers which are replaced by a crown wall designed using structural and functional criteria. Conversely, the continuation of monolithism with parapets anchored to the caissons or in situ concreted onto their cellular body in vertical breakwaters guarantee their rigidity, operability and use against maritime climate forces. The British Standard provides different finishes on the basis of repairing and maintaining the layers and quantifying overtopping by functionality factors (Figure 1). The capability of using anchoring elements allowing for curved walls, greater slenderness, damping chambers, systems taking advantage of wave energy, stress decrease with breather hoses in vertical breakwaters amongst other aspects increases their possibilities. Studying a crown wall has always been approached from the position of thrusts and/or forces on the face and the calculation of run-up and over-topping associated with operations: admissible overtopping rate and volume (EurOtop, 2016). For example, a rate of q = 10 l/s per m implies significant overtopping for dikes, seawalls and embankments.